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FOX News Network - We Report. You Decide. A strong 7.0-magnitude earthquake struck close to New Zealand's second-largest city of Christchurch early Saturday local time, wreaking havoc on buildings, roads and infrastructure. NASA is developing an ambitious new mission to plunge a car-sized probe directly into the sun's atmosphere, boldly going where no spacecraft has gone before. Wolf spiders and carnivorous plants called sundews may compete with each other for food in the wild, a new study finds. Samsung's first tablet computer, the Galaxy Tab, will go on sale in two weeks -- joining the Dell Streak and a slew of Google-powered pads, all trying to turn up the heat on the Apple iPad. The showdown over 3Par Inc. that ended Thursday was a puzzling spectacle. It pitted two of the world's biggest technology companies against each other for control of a company that was obscure outside of technology circles and flat-out unloved on Wall Street, with a stock that was stuck around $10 for a year and a half. Why? A German bomber shot down in World War II has been found 50 feet below the sea off the coast of England. An Indonesian volcano that was quiet for four centuries shot a new, powerful burst of hot ash more than 10,000 feet in the air Friday, sending frightened residents fleeing to safety for the second time this week. Don't worry if you see a Klingon strolling down the street with a mummy this weekend in Atlanta. It's just Dragon Con. All-seeing eye of Sauron? Cosmic sunflower? Not quite. It's actually a massive sunspot as you've never seen one before, captured in stunning high resolution. Earl is moving up the East Coast, and the U.S. Coast Guard is getting ready, moving hundreds of thousands of tons of planes, boats and rescue gear into position. The Guard hopes for the best -- and prepares for the worst. NASA scientists flew Thursday into Hurricane Earl to gather data about what makes some tropical storms strengthen into destructive hurricanes while most fizzle. Invisible shrimp could very well be living in every drop of water you drink -- but that's OK, they're nothing to worry about. U.S. communications regulators on Wednesday put off a controversial decision on Internet traffic rules, giving industry and consumer groups a chance to forge a compromise while avoiding a politically sensitive issue ahead of the November elections. Target has begun selling gift cards for Facebook credits, letting consumers spend real money on fake money to buy gear in online apps and games such as Farmville. The chief of the U.N.'s telecommunications agency is urging BlackBerry's manufacturer to allow foreign law enforcement agencies access to its customers' data. Physics was the reason for the Big Bang, not God, according to scientist Stephen Hawking. A hurricane warning was issued for North Carolina on Wednesday as Hurricane Earl barreled toward the East Coast packing winds of 125 mph. At an annual music-themed event Wednesday, Apple CEO Steve Jobs unveiled an updated streaming TV device, funky new iPods -- and a social network that's all about music. Apple fans Web-wide tuned in to an annual music-themed event Wednesday, where Steve Jobs unveiled an updated streaming TV device, funky new iPods -- and a social network that's all about music. Archaeologists in Jordan have unearthed a 3,000-year-old Iron Age temple with a trove of figurines of ancient deities and circular clay vessels used for religious rituals, officials said Wednesday.FOXNews.com
Do not pass go. Do not collect $200. Just agree to a lifetime of hyper-accurate real-time location tracking. The future of incarceration is just one of our favorite posts this week. This week in the future on PopSci: You can win this illustration on a t-shirt. Leave a comment to put your name in the pile; we'll randomly choose and announce our winner right here. And, if you just can't wait that long, you can buy the shirt for yourself here. Good luck! Until next time, enjoy our past weekly illustrated roundups here. An artificial kidney powered by the circulatory system could be the first implantable device to replace kidney donation and dialysis, scientists say. Led by a University of California-San Francisco scientist, a consortium of about 10 different research teams unveiled a new artificial kidney prototype this week, saying a room-sized version has already shown promise for the sickest patients. Fabrication processes used to make silicon chips could conceivably be used to make coffee-cup-sized devices, which could take thousands of people off dialysis machines or kidney-donor waiting lists. The multi-institutional team, led by UCSF professor Shuvo Roy, formerly of the Cleveland Clinic, is the first to demonstrate technology that could be feasibly downsized into a transplant device. It's a two-stage system involving thousands of nanoscale filters placed in a "BioCartridge," which would remove toxins from the blood. A "HemoCartridge" bioreactor made of engineered renal tubule cells would mimic the metabolic and water-balancing roles of a real kidney. The system uses a patient's blood pressure to perform filtration without the use of pumps, according to a UCSF news release. Currently, transplants and dialysis are the only ways to treat kidney failure. An implantable device would obviously be preferable, but so far, scientists have not been able to come up with a system that mimics everything the kidney can do. The new system relies on the latest advances in nanotechnology and tissue generation, Roy said. He hopes to use silicon-fabrication technology to make the device small enough for transplant. "This could dramatically reduce the burden of renal failure for millions of people worldwide, while also reducing one of the largest costs in U.S. healthcare," he said. An accidental chemistry discovery could lead to a new method for making antifreeze, moisturizer and plastic bottles out of biomass rather than petroleum, according to researchers at Iowa State University. Professor Walter Trahanovsky was using a high-temperature chemistry process to see if he could obtain sugar derivatives from cellulose. It's based on supercritical fluids, which are heated under pressure until their fluid and gas states merge. It is not quite as exotic as it sounds - supercritical carbon dioxide is used to decaffeinate coffee. Trahanovsky and his colleagues put cellulosic materials in alcohols and subjected them to high temperatures and pressures. They got the sugars they were looking for, but they also found something else: significant amounts of propylene glycol and ethylene glycol. This was totally unexpected, Trahanovsky said. Anyone who has ever read a body-lotion bottle would recognize the name propylene glycol - it's a key moisturizing ingredient. It is used in a variety of products, including as a food additive. Ethylene glycol is most commonly used in antifreeze, polyester fabric and plastic bottles. The supercritical fluid process could be a better way to obtain these materials from biomass instead of petroleum. Current biomass-refining processes require strong acids or other harmful or expensive reagents, and the processes also generate hazardous waste. Trahanovsky said the process also produces sugar compounds that can be converted into glucose for ethanol production or other uses. The Iowa State University Research Foundation Inc. filed for a patent based on his technology. In a mission to learn more about the sun's inner workings, NASA is planning to launch a specially shielded spacecraft in 2018 that will plunge into the solar atmosphere. The car-sized Solar Probe Plus will explore an area just 4 million miles from the star's surface, the last region of the solar system to be explored by humans. NASA just announced five science experiments that will fly on the scorching probe, which will be protected by a carbon-fiber heat shield that can withstand temperatures of 2,500 degrees F. When the probe is 4 million miles away, the solar disk will loom 23 times wider in the sky than it does on Earth.Popular Science - Science



The SWEAP solar wind experiment will count the electrons, protons and helium ions in the solar wind and measure their properties. It will also catch some in a special cup for analysis.
Another science mission will use a wide-field camera to take 3-D pictures of the solar wind as the spacecraft flies through it. Another will take direct measurements of the sun's magnetic fields, radio emissions and shock waves, and the one more will take an inventory of the sun's contents.
"For the very first time, we'll be able to touch, taste and smell our sun," said Lika Guhathakurta, Solar Probe Plus program scientist at NASA headquarters.
NASA's goals are to figure out why the sun's corona is several hundred times hotter than the surface and why it produces an accelerating solar wind. Scientists already have high-resolution images and data of the transition zone between the atmosphere and the surface, and the solar wind has been studied extensively - but still, no one can answer some fundamental questions about the sun's evolution. The only way to do it is to go to the source, NASA says. Here's hoping the spacecraft doesn't get burned.
[NASA]
Miss the good old days of daily oil disaster news? Worry not, for another oil rig in the Gulf of Mexico exploded this morning, leaving all 13 crew members in the water but - according to initial reports - all are alive and only one is injured. The rig is owned by Mariner Energy (somewhere a BP exec is breathing again) and is not currently producing, according to the Coast Guard. Updated. Details are sketchy right now, but rescuers are en route to the site about 80 miles south of the central Louisiana coast. We'll update as this one develops.
Update: Reuters is reporting that the Coast Guard has spotted a one-nautical-mile by 100-foot oil sheen in the water at the site of the rig explosion. The fire has been contained, but the flames have not yet been completely extinguished.
Update: USA Today now reports that the initial claim of an oil sheen by Mariner Energy cannot be confirmed by the Coast Guard, and that an aerial flyover by Mariner personnel could not locate the oil sheen reported earlier. In other good news, the fire aboard the oil platform has now been extinguished.
[NYT]

A particularly mind-bending (and controversial) physics paper surfaced in the past week that should make you feel pretty special. It seems the laws of physics can change after all, and it just so happens they're uniquely suited for us right here, right now.
The paper, recently submitted to Physical Review Letters and posted to the physics arXiv, suggests the fine structure constant is not actually constant at all. This could mean that if we were in a different place or time period, atoms would not stay together and nothing - neither planets nor people - could exist.
A team led by John Webb at the University of New South Wales, Australia, has been studying whether the fine structure constant, otherwise known as alpha, changes over time. Alpha is a special number that essentially describes the strength of the electromagnetic force. The famous physicist Richard Feynman called its value "one of the greatest damn mysteries of physics." If it is not 1/137.036, things fall apart.
If alpha was different in the past, the universe might have looked different, too, which could be determined by looking at distant interstellar gases and how they absorb light. Observations by Webb and others at the Keck Observatory in Hawaii suggest that this is exactly the case - over time, alpha has changed ever so slightly.
Competing studies did not find the same result, however, so this is still a controversial idea. But it's a fair bet Webb's follow-up is even more tendentious: He says alpha also changes over space. According to his theory, we're smack in the Goldilocks zone, where alpha is exactly the right value to make matter possible.
This paper happened because Webb and his team wanted to reexamine their Keck findings, which suggested alpha was a tiny bit smaller about 9 billion years in the past. They went to the Very Large Observatory in Chile to check it out, and were shocked by what they saw: the further they looked, the bigger alpha got. The discrepancy is even stranger given the two telescopes' positions: they are in two different hemispheres, so they look in two different directions.
So, to recap: in one direction, alpha was once smaller; in exactly the opposite direction, it was once bigger. This implies that alpha continuously varies throughout space. As Technology Review's physics blog puts it, that's a mind-blowing result. If it's true and can be verified, it could mean the universe is much larger than what we can see, and that the laws of physics vary within it.
It would not be possible for our type of life to exist in a place where alpha were any different. So here's to here and now.

The father of evolution apparently played God with a tropical ecosystem 160 years ago, and the results could inform future experiments to terraform Mars, botanists say.
The BBC recounts how Charles Darwin helped build an artificial forest on Ascension Island, one of his subjects of study from his trips on the HMS Beagle. Today, the island is home to species of plants that would not naturally co-exist. Darwin and his friends put them there, and nearly two centuries later, their grand experiment is living proof that we can transform natural environments.
Originally used as an outpost to keep an eye on Napoleon in exile, Ascension Island, between South America and Africa, was a busy Atlantic waystation in Darwin's day. It had meager fresh water supplies, however, so Darwin and his botanist friend, Joseph Hooker, set out to change things.
The BBC interviews Darwin biographer David Catling, a professor at the University of Washington-Seattle, who says he believes Darwin decided to build a lush "Little England" on the volcanic island after visiting it in 1836.
Darwin's friend Hooker explored Ascension a few years later, and in 1847, Darwin convinced Hooker to get his father -- director of the Kew Gardens -- to send trees, hoping they would capture rain, prevent erosion and reduce evaporation.
Beginning in 1850 and continuing each year, ships brought an assortment of plants from botanical gardens in Europe, South Africa and Argentina, the BBC says. By the late 1870s, eucalyptus, Norfolk Island pine, bamboo, and banana had taken hold.
Today, Ascension is home to a cloud forest that would have taken millions of years to evolve naturally, according to Dave Wilkinson, an ecologist at Liverpool John Moores University in the UK.
It's proof that humans can build a fully functioning ecosystem simply through trial and error, he said. As the BBC reports, the same principle could be used in future Mars colonies: "Rather than trying to improve an environment by force, the best approach might be to work with life to help it find its own way."
Intelligent design, indeed.

East Coast residents are bracing for this monster, headed their way with 125-mph winds, as a fleet of NASA satellites and airplanes monitors its evolution.
As of Wednesday morning, Hurricane Earl was a Category 3 storm, but an especially large one. Storm-force winds extend 200 miles from its eye, seen above in a photo snapped from the International Space Station.
NASA scientists are flying airplanes into this swirling mass, measuring the hurricane's wind speeds, precipitation and more. As part of NASA's GRIP program - Genesis and Rapid Intensification Processes - a NASA DC-8 flew through Earl's eye six times as the hurricane intensified from a Category 2 to a Category 4 storm.
Meanwhile, an ISS crew member used a digital camera with a 50mm lens to take the above photo, from a much safer distance.

Apparently, some tigers can change their stripes -- especially if they have books to sell. One of our favorite climate villains, the Danish economist Bjørn Lomborg, has apparently warmed to the idea of climate change, and now says it's a problem on which the world ought to spend $100 billion annually.
Lomborg's forthcoming book, Smart Solutions to Climate Change, declares that global warming is "undoubtedly one of the chief concerns facing the world today." He examines eight methods to reduce or stop it, including wave, wind, solar and nuclear power, as well as geoengineering, and advocates a carbon emissions tax to finance investment.
As the British media points out, it's a nice U-turn from a man whom the UN climate chief once compared to Adolf Hitler. In a great example of climate politics making strange bedfellows, the same UN chief, Rajendra Pachauri, provides a book-jacket endorsement: "This book provides not only a reservoir of information on the reality of human-induced climate change, but raises vital questions and examines viable options on what can be done."
In an interview with the Guardian, Lomborg explains that he reached his conclusions like any good economist: By studying the numbers. In 2004, economists at Lomborg's Copenhagen Consensus think tank were asked how they'd spend $50 billion to solve the world's problems. They ranked climate change near the bottom of the priority list, below issues like HIV and malaria. But four years later, economists tackled the question again, and interest in climate change had risen like the polar temperatures. Lomborg said this prompted him to consider new climate change policies, so global warming wouldn't languish at the bottom of the list.
Earlier this summer, we ripped Lomborg for railing against programs and treaties that aim to lessen or halt anthropogenic climate change. Now that he says it should be a top priority, we'll take him off our villain list. And give him credit for his media savvy -- the guy knows how to sell books.

Is everything in the universe made up of vibrating one-dimensional strings? For the first time, scientists think they can concretely test string theory, the mind-blowing "theory of everything" that has dominated physics for the past two decades. It turns out that string theory predicts the behavior of entangled quantum particles, which can be tested in a lab - therefore testing string theory.
String theory elegantly reconciles the otherwise competing rules of quantum mechanics and general relativity. It's the most widely accepted unified field theory, but it remains controversial. It basically posits that electrons and quarks are not objects, but one-dimensional strings, whose oscillation gives them their observed qualities. The most fun element of string theory is the requirement that the universe has about a dozen dimensions, rather than the usual four (length, width, height and time).
M-theory, the dominant version of string theory, holds that the universe is made up of unfathomably small slices of a 2-dimensional membrane, wriggling in 11-dimensional space.
These bizarre ideas are widely accepted by many theoretical physicists, but the problem is that they can't be tested - how do you examine an 11th dimension? The field has suffered a backlash in recent years partly for this reason, as some scientists say a theory is not a theory if its predictions can't be studied in a lab.
Well, now they can, according to professor Mike Duff of the theoretical physics department at Imperial College London. He is lead author of a paper to be published tomorrow in Physical Review Letters, which explains how string theory math can be used to predict quantum entanglement.
Duff said he was at a conference in Tasmania when a colleague presented some mathematical formulas describing entanglement of multiple quantum bits. The equations looked familiar. Upon returning home, Duff checked his notebooks from a few years earlier, and realized the formulas were the same as those he developed to use string theory to describe black holes.
This is completely unexpected, he said. There is no obvious reason why the insanely complex mathematics underlying string theory can also be used to predict the behavior of entangled quantum systems.
"This may be telling us something very deep about the world we live in, or it may be no more than a quirky coincidence," he said.
Either way, it's useful, he added. Using string theory math, Duff predicted the pattern that would occur when four quantum bits are entangled with each other. This can be measured in a lab, and the results will demonstrate whether string theory actually works.
Right now, the best hope for string theory tests comes from CERN's Large Hadron Collider, which is designed to find the tiniest elementary particles that make up matter. It's theoretically possible that LHC experiments will uncover supersymmetric particles - one element of string theory - or bounce a graviton into a higher dimension, which could help prove M-theory. But testing the fuzzy math that predicts these behaviors will be much easier.
Technology Review exists to promote the understanding of emerging technologies and their impact. People divulge more sensitive information on sites that look less safe. Researchers at Carnegie Mellon University have found that the appearance of website has a big effect on how honestly people answer personal questions put to them by the site. But paradoxically, it turns out we're more likely to spill our secrets on websites that appear less reputable. The way a website phrases questions also affects our willingness to disclose revealing information, the researchers found. NudgeCam encourages good footage by tracking faces and assessing sound quality. If you've ever accidentally shot a video sideways, or cropped the top of someone's head out of a frame, you might be glad to know about a new cell-phone app that automatically provides shooting advice to videographers. A computer model that detects who is influencing whom in a group discussion, can accurately predict who is likely to speak next One fascinating question that occupies social scientists concerns groups discussions. The problem is to determine the nature of the interaction between individuals and in particular, who influences whom. Millions of Web surfers have spare computer cycles--why not use browsers to tap them? Unless a flash ad in one of your open browser tabs has gone rogue, it's likely you've got a few spare processor cycles available on the PC you're using to read this. The largest-ever storm monitoring mission is now gathering scientific data that was previously impossible to get. As Hurricane Earl barrels toward the eastern seaboard of the United States, coastal residents don't know if they should evacuate in case the storm makes landfall. They rely on forecasters analyzing computer models, but those predictions differ. A new hurricane-monitoring mission that's now underway hopes to reduce this uncertainty by gathering atmospheric and environmental storm data never before obtained. The next few years will see at least two new commercial spacecraft put into orbit. A small fleet of privately developed spacecraft will head into orbit in the next few years--assuming that current levels of public and private funding can be sustained. If it happens, this will mark a new chapter in space exploration and research, as NASA comes to rely more on private companies for the technology to put manned and unmanned vehicles in space. Scientists examine new ways to manipulate the microorganisms within us. Earlier this summer, scientists reported the success of an unusual medical transplant; a woman with a life-threatening Clostridium difficile infection was treated, and apparently cured, with an injection of some of her healthy husband's gut bacteria. Researchers are now exploring the effects of this type of transplant in greater detail. They hope to eventually treat a wide range of ailments--from bowel diseases to obesity, diabetes to depression--by manipulating the bacteria that live in the human gut. A new way of excavating the past structure of networks reveals important information about their evolution The agency announced its latest revision but budget uncertainties in the U.S. Congress make plans moving targets. Researchers inject quantum dots into the skin using plastic microneedles, potentially providing a way to diagnose and treat diseases. Using a novel laser-based technique, researchers at North Carolina State University have made arrays of tiny, hollow plastic needles that they used to insert fluorescent quantum-dot dyes into skin. Biomedical engineering professor Roger Narayan, who leads the research, says the microneedles and quantum dots, which have been tested on pigs, could be used to diagnose and treat skin cancer and other chronic diseases. For years, claims have circulated that red rain which fell in India in 2001, contained cells unlike any found on Earth. Now new evidence that these cells can reproduce is about to set the debate alive Panspermia is the idea that life exists throughout the universe in comets, asteroids and interstellar dust clouds and that life of Earth was seeded from one or more of these sources. Panspermia holds that we are all extraterrestrials. The National Institute of Health announces the grants for research aboard the space station. The National Institute of Health (NIH) has awarded the first new grants for biomedical research on the International Space Station (ISS). The grants are part of an initiative between NIH and NASA to spur research on health issues in microgravity. "Dustcart" finished a test run in Italy, successfully making house calls to collect garbage. In the Italian town of Peccioli the streets are too old and narrow for garbage trucks to navigate, so residents have had to manage their own trash collection. That is, until the appearance of this summer of "Dustcart," a Segway-wheeled, sensor-equipped robot that responds to house calls to collect garbage. Music-focused social network is linked to iTunes, and TV shows will rent for 99 cents. Technology Review RSS Feeds
Technology Trends and GadgetsTrendHunter.com - Technology Trends and Gadgets
The Lenco L-71 Turntable brings the 70s into the 21st century with its groovy reading and encoding capabilities. The product is complete with a belt drive turntable that can copy your old favorite bands…
These Korean UFO Bluetooth Speakers resemble flying saucers, perfect for those obsessed with outer space.
Capable of being both a sound system and an mp3 player, these Korean UFO Bluetooth speakers also…
Mads Hindhedes’ BabelFisk glasses takes verbal speech and translates it into readable text right before your very eyes.
With speech recognition software combined with hearing aid algorithms, the result…
Stussy and Zozotown are collaborating to create a line of skate fashion-inspired cases for the iPhone 4 to kick off Zozotown's New Design Project Volume 2.
The cases don graffiti art straight from…
If you are a parent who knows the hassle of baby monitors, you may appreciate these featured Exmobaby Biosensor Pajamas.
These interesting Exmobaby Sensor Pajamas incorporate a baby monitor within the…
Konica Minolta and Agent have collaborated to launch OLEH Lighting Concepts as an exploration of new OLED technology applications. The team has come up with both Strip Light and Wearable concepts.
This…
If you love Apple and their products as much as you say you do, then you will welcome the Plush iMac into your house with arms wide open. This pillow was designed by Kerry Hughes to look exactly like an…
The first living organism beyond the occasional teenager to rely solely on social media for survival is the Meet Eater plant. That plant was a social experiment by a student at the University of Queensland…
The Rec & Play pen is an extraordinary hybrid writing tool. Essentially, it "combines sound, sight and physical movement," according to PSFK, creating the most practical piece of stationary you could ever…
The GreenTek ‘Solar Mug’ is like no mug you’ve ever encountered. Not only is the thermos equipped with a temperature control to keep your coffee at your heated preference, but cold temperatures can be…
The Negawatt iPhone app is exactly what you need to become a green homeowner. The application is intended to help users become more energy efficient in their homes. Giving advice about the way users light…
It seems like the Ohnoya Hotel in Atami, Japan, has taken a strong interest in the virtual dating game 'Love Plus,' and is target men with virtual significant others. Putting a new spin on the virtual…
Swarovski and Philips have teamed up again to create USBs for the geeky-glamorous. However, this collection is geared towards animal-lovers. Who wouldn’t want one of these adorable little animal USBs?…
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Virtual Journal of Nanoscale Science & TechnologyVirtual Journal of Nanoscale Science & Technology
We derive the Markovian description for the nonequilibrium Brownian motion of a heated nanoparticle in a simple solvent with a temperature-dependent viscosity. Our analytical results for the generalized fluctuation-dissipation and Stokes-Einstein relations compare favorably with measurements of lase ... [Phys. Rev. Lett. 105, 090604 ] published .
The Si(553)-Au surface consists of a periodic array of single steps and (111) terraces with a quasi-one-dimensional electronic structure. In this paper, the determination of the atomic structure of this surface with x-ray diffraction is reported. The gold coverage of the surface was measured to be 0 ... [Phys. Rev. B 82, 075426 ] published .
We examine hydrogen sorption cycling of 1.5 [mu]m thick magnesium thin films containing a bimetallic chromium titanium catalyst. At 200 degrees C these nanocomposites absorb 5 wt % hydrogen in several seconds, and desorb in 1020 minutes. In several compositions, there is negligible hydrogenation ... [Appl. Phys. Lett. 97, 083106 (2010)] published Thu Aug 26, 2010.
Synthetic diamond has potential as a heat spreading material in small-scale devices. Here, we report thermal conductance values at interfaces between aluminum and diamond with various surface terminations over a range of temperatures from 88 to 300 K. We find that conductance at oxygenated diamond i ... [Appl. Phys. Lett. 97, 083102 (2010)] published Mon Aug 23, 2010.
We reveal the presence of atomic short-range ordering at the interface between crystalline beta-SiN and amorphous SiO using aberration-corrected scanning transmission electron microscopy. We show that the first atomic layers of the amorphous SiO film reconstruct taking on the crystalline form of SiN ... [Phys. Rev. B 82, 081412 ] published .
This paper describes a solvothermal approach to synthesize CuInS quantum dots (QDs) and demonstrates their application as a potential electron accepting material for polymer-based hybrid solar cells, for the first time. The CuInS QDs with a size of 24 nm are synthesized by the solvothermal method wi ... [J. Mater. Chem. 20, 7570 (2010)] published Wed Aug 25, 2010.
This work is aimed at producing uniform microporous polymer nanoparticles (MPNs) and studying their hydrogen storage properties. Synthesis of vinylbenzyl chloride (VBC)/divinylbenzene (DVB) copolymers by emulsion polymerization yield fairly uniform gel-type precursor nanoparticles and the particle s ... [J. Mater. Chem. 20, 7444 (2010)] published Wed Aug 25, 2010.
Periodic mesoporous organosilicas (PMOs) with methylene (CH), ethylene (CHCH), ethenylene (CH[double bond, length as m-dash]CH) and phenylene (CH) framework groups were synthesized with 2-dimensional hexagonal structures of very large cylindrical mesopores. A combination of a commercially available ... [J. Mater. Chem. 20, 7506 (2010)] published Wed Aug 25, 2010.
This study is concerned with electrochemical investigation of novel high-performance proton exchange membranes based on bio-functionalized montmorillonite and Nafion[registered sign]. It was found that the incorporation of 2 wt% BMMT into Nafion[registered sign] polyelectrolyte matrix results in sig ... [Chem. Commun. 46, 6500 (2010)] published Wed Aug 25, 2010.
Micro- and nano-scale protein patterns have gained significant technological interest. While certain techniques for single-component protein patterning are well-established, multicomponent protein patterning approaches are a current topic of intensive research, which might enable complex biosensor s ... [J. Mater. Chem. 20, 7322 (2010)] published Wed Aug 25, 2010.
Fatty acid modified Mn derivatives can self-assembly into vesicular structures in organic media. The vesicular assemblies have a sandwich structure with Mn cluster separated by two alkyl chain layers. ... [Chem. Commun. 46, 6548 (2010)] published Wed Aug 25, 2010.
Periodic mesoporous titanium phosphonate materials (PMTP-1) with bridged-organic groups inside the framework are synthesized by an autoclaving process combined with the evaporation-induced self-assembly (EISA) strategy, with the assistance of surfactant Brij 56 (CEO). Sodium salt of ethylene diamine ... [J. Mater. Chem. 20, 7406 (2010)] published Wed Aug 25, 2010.
Porous materials find widespread application in storage, separation, and catalytic technologies. We report a crystalline porous solid with adaptable porosity, in which a simple dipeptide linker is arranged in a regular array by coordination to metal centers. Experiments reinforced by molecular dynam ... [Science 329, 1053 ] published .
Abstract not available. [Phys. Rev. B 82, 089902 ] published .
The exciton and biexciton lines of a single quantum dot are deterministically coupled to the optical modes of a photonic molecule. The resonance between the quantum dot emission lines and the molecule cavity modes is reached at 53 K. The device operates as a very bright source of entangled photon pa ... [Appl. Phys. Lett. 97, 081104 (2010)] published Mon Aug 23, 2010.
The I inequality is the simplest bipartite two-outcome Bell inequality beyond the Clauser-Horne-Shimony-Holt (CHSH) inequality, consisting of three two-outcome measurements per party. In the case of the CHSH inequality the maximal quantum violation can already be attained with local two-dimensional ... [Phys. Rev. A 82, 022116 ] published .
Measurement devices could benefit from entangled correlations to yield a measurement sensitivity approaching the physical Heisenberg limit. Building upon previous magnetometric work using pseudoentangled spin states in solution-state NMR, we present two conceptual advancements to better prepare and ... [Phys. Rev. A 82, 022330 ] published .
We report measurements of macroscopic resonant tunneling between the two lowest energy states of a pair of magnetically coupled rf-superconducting quantum interference device flux qubits. This technique provides both a direct means of measuring the energy gap of the two-qubit system and a method for ... [Phys. Rev. B 82, 060512 ] published .
We report on the effects of quantum interference induced by the transmission of an arbitrary number of optical quantum states through a multiple-scattering medium. We identify the role of quantum interference on the photon correlations and the degree of continuous variable entanglement between two o ... [Phys. Rev. Lett. 105, 090501 ] published .
We compute the quantum correlation [quantum discord (QD)] and the entanglement (EOF) between nearest-neighbor qubits (spin-1/2) in an infinite chain described by the Heisenberg model (XXZ Hamiltonian) at finite temperatures. The chain is in the thermodynamic limit and thermalized with a reservoir at ... [Phys. Rev. Lett. 105, 095702 ] published .
We show that the carrier-mediated exchange interaction, the so-called Ruderman-Kittel-Kasuya-Yoshida (RKKY) coupling, between two magnetic impurity moments in graphene is significantly modified in the presence of electron-electron (el-el) interactions. Within the mean-field approximation of the Hubb ... [Phys. Rev. B 82, 073409 ] published .
The effect of thermal annealing treatment on the morphology change in bulk heterojunction (BHJ) in organic photovoltaic cells was studied by photoemission spectroscopy. The results reveal that vertical phase separation upon annealing occurs in typical BHJ layer formed between planar molecule CuPc an ... [Appl. Phys. Lett. 97, 083302 (2010)] published Tue Aug 24, 2010.
The selective electroless coating of palladium (Pd) nanoparticles on metallic single-walled carbon nanotube (SWNT) was studied. The remarkable increase in conductivity of SWNT/Pd films up to fourfold higher than pure SWNT was due to p-type doping and Ohmic contact. Metallic behavior of SWNT/Pd-Field ... [Appl. Phys. Lett. 97, 083101 (2010)] published Mon Aug 23, 2010.
We describe a technique for the fabrication of individual carbon nanotube electron field emitters on silicon substrates, with well-defined tunneling geometries and robust metal contacts. The suspended nanotube emitters have been produced by edge lithography on cleaved silicon substrate in conjunctio ... [Appl. Phys. Lett. 97, 073119 (2010)] published Fri Aug 20, 2010.
We demonstrate that the use of a microcavity structure can overcome the trade-off between exciton diffusion and optical absorption in planar heterojunction organic photovoltaic cells. Optical simulation based on the copper phthalocyanine (CuPc)-fullerene donor-acceptor system showed that the microca ... [Appl. Phys. Lett. 97, 083306 (2010)] published Tue Aug 24, 2010.
We study all possible band-to-band transitions between 12 valence and 16 conduction bands of (8,0), (10,0), and (7,0) nanotubes and calculate the corresponding dipole moments using first-principles methods in a wide ultraviolet-visible-infrared range of photon energies. The goal is to investigate th ... [Phys. Rev. B 82, 085442 ] published .
We have investigated the anisotropic dynamic dielectric response of aligned and well-isolated single-walled carbon nanotubes using optical-pump terahertz (THz)-probe techniques. The polarization anisotropy measurements demonstrate that the THz radiation interacts only with radiation polarized parall ... [Phys. Rev. B 82, 085441 ] published .
Electronic structures of (6,0), (8,0), and (10,0) single-walled boron nitride nanotubes (SWBNNTs) subjected to tension, torsion, and flattening are investigated using first-principles calculations. Energy bands and charge distributions of the SWBNNTs are calculated within the density-functional theo ... [Phys. Rev. B 82, 085433 ] published .
We report an inelastic neutron-scattering (INS) investigation of coupled quantum translation and rotation of hydrogen molecules trapped inside the closed isotropic cages of C. The low-lying states that characterize the translation-rotation manifold of the hydrogen molecules are accurately determined ... [Phys. Rev. B 82, 081410 ] published .
We employ state-of-the-art first-principles calculations based on density-functional theory and density-functional perturbation theory to investigate relevant physical properties and phase diagram of the free guest type-I (X-46) and type-II (X-34) carbon clathrates. Their properties and those of sil ... [Phys. Rev. B 82, 075209 ] published .
The unique topology and exceptional properties of carbon nanoscrolls (CNSs) have inspired unconventional nanodevice concepts, yet the fabrication of CNSs remains rather challenging. Using molecular dynamics simulations, we demonstrate the spontaneous formation of a CNS from graphene on a substrate, ... [Appl. Phys. Lett. 97, 081909 (2010)] published Thu Aug 26, 2010.
The open-circuit voltage (V) of bulk heterojunction solar cells based on polymers and fullerene derivatives is limited to ~1.15 V by the optical band gap of the fullerene of ~1.75 eV and the required 0.6 eV offset for efficient charge generation. In practice this limit has not yet been reached. We ... [Appl. Phys. Lett. 97, 073304 (2010)] published Fri Aug 20, 2010.
We investigate the nonlinear optical properties of graphene flakes using four-wave mixing. The corresponding third-order optical susceptibility is found to be remarkably large and only weakly dependent on the wavelength in the near-infrared frequency range. The magnitude of the response is in good a ... [Phys. Rev. Lett. 105, 097401 ] published .
Multilayer graphene on the carbon face of silicon carbide is an intriguing electronic system which typically consists of a stack of ten or more layers. Rotational stacking faults in this system dramatically reduce interlayer coherence. In this paper we report on the influence of interlayer interacti ... [Phys. Rev. B 82, 085443 ] published .
We studied the in-plane magnetoresistance R(B,T) anisotropy in epitaxial multilayer graphene films grown on the Si face of a 6H-SiC substrate that originates from steplike morphology of the SiC substrate. To enhance the anisotropy, a combination of argon atmosphere with graphite capping was used dur ... [Phys. Rev. B 82, 085438 ] published .
The electrical conductivity of graphene containing point defects is studied within the binary alloy model in its dependence on the Fermi-level position at the zero temperature. It is found that the minimal conductivity value does not have a universal character and corresponds to the impurity resonan ... [Phys. Rev. B 82, 085436 ] published .
Graphene is a two-dimensional material with exceptional electronic properties and enormous potential for applications. Graphene's promise as a chemical sensor material has been noted but there has been little work on practical chemical sensing using graphene, and in particular, how chemical function ... [Appl. Phys. Lett. 97, 083107 (2010)] published Thu Aug 26, 2010.
Electronic properties of the graphene layer sandwiched between two hexagonal boron nitride sheets have been studied using the first-principles calculations and the minimal tight-binding model. It is shown that for the ABC-stacked structure in the absence of external field the bands are linear in the ... [Phys. Rev. B 82, 085431 ] published .
Solidsolid phononic crystals exhibit wider band gaps than those observed with airsolid phononic crystals. For micromachined phononic crystal devices it is advantageous to release the phononic crystal to avoid propagation losses. In a solidsolid phononic crystal operating in the low megahertz range, ... [Appl. Phys. Lett. 97, 081907 (2010)] published Wed Aug 25, 2010.
Multilayer Soft Lithography (MSL) is a robust and mature fabrication technique for the rapid prototyping of microfluidic circuits having thousands of integrated valves. Despite the success and wide application of this method, it is fundamentally a planar fabrication technique which imposes serious d ... [Lab Chip 10, 2358 (2010)] published Wed Aug 25, 2010.
Although pathologic changes to the structure and function of small blood vessels are hallmarks of various cardiovascular diseases, limitations of conventional investigation methods (i.e. pressure myography) have prohibited a comprehensive understanding of the underlying mechanisms. We developed a mi ... [Lab Chip 10, 2341 (2010)] published Wed Aug 25, 2010.
Here we report an approach utilizing a suspended nanoparticle crystal (S-NPC) as an electrical read-out biosensor based on a nanofluidic electrokinetics principle. As a preliminary demonstration, streptavidin-modified S-NPC with a particle diameter of 520 nm was used to detect biotin in a PBS buffer ... [Lab Chip 10, 2338 (2010)] published Wed Aug 25, 2010.
A complementary metal-oxide semiconductor (CMOS)-compatible, capacitive, shunt-type radio frequency MEMS switch design is demonstrated. The switch is actuated by an electrothermal actuator and an electrostatic actuator at the same time, and the switching status is latched by electrostatic force only ... [J. Micro/Nanolith. MEMS MOEMS 9, 033008 (2010)] published Thu Aug 26, 2010.
High resolution live cell microscopy is increasingly used to detect cellular dynamics in response to drugs and chemicals, but it depends on complex and expensive liquid handling devices that have limited its wider adoption. Here, we present a microfluidic perfusion system that is built without using ... [Lab Chip 10, 2449 (2010)] published Wed Aug 25, 2010.
In this study, we have developed a meander-shaped dynamic microfluidic technology that allows us to pair two different types of microbeads in a trapping site. The dynamic microfluidic technology comprises implemented modifications of a conventional dynamic microarray design such as: (i) the combinat ... [Lab Chip 10, 2443 (2010)] published Wed Aug 25, 2010.
Creating multicellular tumor spheroids is critical for characterizing anticancer treatments since it may provide a better model than monolayer culture of tumor cells. Moreover, continuous dynamic perfusion allows the establishment of long term cell culture and subsequent multicellular spheroid forma ... [Lab Chip 10, 2424 (2010)] published Wed Aug 25, 2010.
In this letter, temperature compensation for aluminum nitride (AlN) Lamb wave resonators operating at high temperature is presented. By adding a compensating layer of silicon dioxide (SiO), the turnover temperature can be designed for high temperature operation by varying the normalized AlN film thi ... [Appl. Phys. Lett. 97, 083501 (2010)] published Mon Aug 23, 2010.
We investigate a setup where a cloud of atoms is trapped in an optical lattice potential of a standing-wave laser field which is created by retroreflection on a micromembrane. The membrane vibrations itself realize a quantum mechanical degree of freedom. We show that the center-of-mass mode of atoms ... [Phys. Rev. A 82, 021803 ] published .
We report high aspect ratio nanochannel fabrication in glass using single-shot femtosecond Bessel beams of sub-3 [mu]J pulse energies at 800 nm. We obtain near-parallel nanochannels with diameters in the range 200800 nm, and aspect ratios that can exceed 100. An array of 230 nm diameter channels wi ... [Appl. Phys. Lett. 97, 081102 (2010)] published Mon Aug 23, 2010.
Since its discovery, the asymmetric Fano resonance has been a characteristic feature of interacting quantum systems. The shape of this resonance is distinctively different from that of conventional symmetric resonance curves. Recently, the Fano resonance has been found in plasmonic nanoparticles, ph ... [Nature Mater. 9, 707 (2010)] published Wed Aug 25, 2010.
We report on some surprising optical properties of diluted nitride InGaAsN/GaAs (epsilon<<1) pyramidal site-controlled quantum dots, grown by metalorganic vapor phase epitaxy on patterned GaAs (111)B substrates. Microphotoluminescence characterizations showed antibinding exciton/biexciton behavior, ... [Appl. Phys. Lett. 97, 072115 (2010)] published Fri Aug 20, 2010.
We analyze the charge dynamics of a superconducting single-electron transistor (SSET) in the regime where charge transport occurs via Cooper-pair resonances. Using an approximate description of the system Hamiltonian, in terms of a series of resonant doublets, we derive a Born-Markov master equation ... [Phys. Rev. B 82, 064519 ] published .
Deposited silicon and, in particular, hydrogenated amorphous silicon forms an attractive alternative platform for realizing compact photonic integrated circuits. In this paper we report on trimming (toward lower wavelengths) and tuning (toward higher wavelengths) of photonic devices through a suitab ... [Appl. Phys. Lett. 97, 071120 (2010)] published Fri Aug 20, 2010.
We explore the coherent transfer of electronic signatures from a strongly correlated, optically gated nanoscale quantum dot to a weakly interacting, electrically backgated microscale channel. In this unique side-coupled T geometry for transport, we predict a mechanism for detecting Rabi oscillations ... [Phys. Rev. B 82, 085324 ] published .
In order to explain the recently observed phenomenon of optical orientation of a single Mn spin residing inside a CdTe quantum dot, a process of Mn spin relaxation with characteristic time scale of tens of nanosecond had been invoked. We show that after taking into account the mixing of states of th ... [Phys. Rev. B 82, 075321 ] published .
Here, we show that the Casimir-Lifshitz force (either attractive or repulsive) between two planar material slabs embedded in a dense array of silver nanowires is an ultralong-range force that decays with the separation of the bodies, a, as 1/a, whereas in an isotropic background it decays as 1/a. It ... [Phys. Rev. A 82, 022511 ] published .
The monodisperse spherical SiO/YO:Tb core/shell particles were prepared by a heterogeneous precipitation coating of the phosphor shell on the surface of the core particles. The shell thickness and the calculated crystallite size were increased with the core size and, thus, the photoluminescence (PL) ... [J. Electrochem. Soc. 157, J358 (2010)] published Wed Aug 25, 2010.
We prepared ZnMnO nanorods by thermal diffusion. These samples were then studied the structural, optical, and magnetic properties. The structural analyses basing on x-ray diffraction and transmission electron microscope revealed the absence of Mn-related secondary phases. The study of photoluminesce ... [J. Appl. Phys. 108, 044910 (2010)] published Tue Aug 24, 2010.
We report experimental investigation on a series of strained Ge/Si heterostructure with various Ge thicknesses (the order of nanometers) grown at low temperatures (260 degrees C). In addition to the conventional uniform intermixing at the Ge/Si interface for structures with thin Ge layer, local int ... [J. Appl. Phys. 108, 044314 (2010)] published Tue Aug 24, 2010.
We report the optical and magnetic properties of ZnO, ZnInO, and ZnInO nanowires (NWs). All samples have similar wirelike shape with an average diameter of about 70 nm and a length of about 10 [mu]m. The comparison of photoluminescence (PL) spectra at 10 K indicated that a new broad emission band a ... [J. Appl. Phys. 108, 043516 (2010)] published Mon Aug 23, 2010.
Using the segmented contact method we separate and numerically evaluate the components making up the threshold current density dependence of quantum dot ridge waveguide lasers. An increasing internal optical mode loss and an increasing lateral out-diffusion current are the significant processes in r ... [J. Appl. Phys. 108, 043108 (2010)] published Thu Aug 26, 2010.
Multiphoton-absorption (MPA) induced ultraviolet (UV) luminescence of ZnO nanorods grown by vapor phase transport was demonstrated using ultrafast excitation at pulse energies in the few nanojoules range, directly generated by a Ti:sapphire laser oscillator at wavelengths around 800 nm. The dependen ... [J. Appl. Phys. 108, 043107 (2010)] published Wed Aug 25, 2010.
We present results of photoluminescence spectroscopy and lifetime measurements on thin film hybrid arrays of semiconductor quantum dots and metal nanoparticles embedded in a block copolymer template. The intensity of emission as well as the measured lifetime would be controlled by varying the volume ... [Appl. Phys. Lett. 97, 083307 (2010)] published Thu Aug 26, 2010.
We study single GaAs quantum dots with optical transitions that can be brought into resonance with the widely used D transitions of rubidium atoms. We achieve resonance by Zeeman or Stark shifting the quantum dot levels. We discuss an energy stabilization scheme based on the absorption of quantum do ... [Appl. Phys. Lett. 97, 082103 (2010)] published Mon Aug 23, 2010.
We show that highly homogeneous cubic GaN can be grown by plasma-assisted molecular beam epitaxy on wurtzite GaN nanowires. The line width of the donor bound exciton is below 3 meV and can reach 1.6 meV in the best parts of the studied sample. This allows to perform a detailed spectroscopy of cubic ... [Appl. Phys. Lett. 97, 081910 (2010)] published Thu Aug 26, 2010.
We propose a method to generate a two-dimensional cluster state of polarization encoded photonic qubits from two coupled quantum dot emitters. We combine the proposal for generating one-dimensional cluster state strings from a single dot, with a new proposal for an induced conditional phase gate bet ... [Phys. Rev. Lett. 105, 093601 ] published .
Carrier lifetime at room temperature (RT) was measured for blue-violet emitting InGaN multiquantum wells as a function of excitation intensity. The carrier lifetime of a p/n-doped waveguide sample (PNLD) was longer than those of undoped or n-doped waveguide samples. For PNLD, the long decay componen ... [Appl. Phys. Lett. 97, 071910 (2010)] published Fri Aug 20, 2010.
A fine-focusing x-ray source has been constructed employing a field electron emitter prepared by growing carbon-nanofibers (CNFs) on a metal tip. The x-ray source is composed of a CNF field electron emitter, an electrostatic lens, two magnetic lenses, and a W-target for generating x-rays by electron ... [J. Appl. Phys. 108, 044507 (2010)] published Thu Aug 26, 2010.
We have developed a new scanning tunneling potentiometry technique which canwith only minor changes of the electronic setupbe easily added to any standard scanning tunneling microscope (STM). This extension can be combined with common STM techniques such as constant current imaging or scanning tunne ... [Rev. Sci. Instrum. 81, 083704 (2010)] published Thu Aug 26, 2010.
We demonstrate a technique in microscopy which extends the domain of atomic force microscopy to optical spectroscopy at the nanometer scale. We show that molecular resonance of feature sizes down to the single molecular level can be detected and imaged purely by mechanical detection of the force gra ... [Appl. Phys. Lett. 97, 073121 (2010)] published Fri Aug 20, 2010.
A scanning tunneling microscope (STM) has been equipped with a nanoscale force sensor and signal transducer composed of a single D molecule that is confined in the STM junction. The uncalibrated sensor is used to obtain ultrahigh geometric image resolution of a complex organic molecule adsorbed on a ... [Phys. Rev. Lett. 105, 086103 ] published .
Electric-field control of magnetization has many potential applications in magnetic memory storage, sensors and spintronics. One approach to obtain this control is through multiferroic materials. Instead of using direct coupling between ferroelectric and ferromagnetic order parameters in a single-ph ... [Nature Mater. 9, 756 (2010)] published Wed Aug 25, 2010.
Magnetic tunnel junctions (MTJs) with ferromagnetic electrodes possessing a perpendicular magnetic easy axis are of great interest as they have a potential for realizing next-generation high-density non-volatile memory and logic chips with high thermal stability and low critical current for current ... [Nature Mater. 9, 721 (2010)] published Wed Aug 25, 2010.
We apply polarization resolved photoluminescence spectroscopy to measure the spin polarization of a two dimensional electron gas in perpendicular magnetic field. We find that the splitting between the sigma and sigma polarizations exhibits a sharp drop at nu=5/2 and is equal to the bare Zeeman energ ... [Phys. Rev. Lett. 105, 096801 ] published .
We present an experimental study of the nucleation rate associated with current-driven vortex oscillations in magnetic nanocontacts. We find that the nucleation and subsequent steady-state oscillation of a vortex can be initiated using current pulses as short as a few nanoseconds, yielding instant o ... [Appl. Phys. Lett. 97, 072512 (2010)] published Fri Aug 20, 2010.
We present a theory of graphene quantum rings designed to produce degenerate shells of single-particle states close to the Fermi level. We show that populating these shells with carriers using a gate leads to correlated ground states with finite total electronic spin. Using a combination of tight-bi ... [Phys. Rev. B 82, 075425 ] published .
The Bi/Si(111) (sqrt(3) x sqrt(3))R30 degrees trimer phase offers a prime example of a giant spin-orbit splitting of the electronic states at the interface with a semiconducting substrate. We have performed a detailed angle-resolved photoemission spectroscopy (ARPES) study to clarify the complex to ... [Phys. Rev. B 82, 085440 ] published .
Experiments where a laser-generated proton beam is used to probe the megagauss strength self-generated magnetic fields from a nanosecond laser interaction with an aluminum target are presented. At intensities of 10 W cm and under conditions of significant fast electron production and strong heat fl ... [Phys. Rev. Lett. 105, 095001 ] published .
The spectrum of two-dimensional (2D) plasma waves in graphene has been recently studied in the Dirac fermion model. We take into account the whole dispersion relation for graphene electrons in the tight-binding approximation and the local-field effects in the electrodynamic response. Near the wave v ... [Phys. Rev. B 82, 073411 ] published .
The effect of electron-electron interaction on the low-temperature conductivity of graphene is investigated experimentally. Unlike in other two-dimensional systems, the electron-electron interaction correction in graphene is sensitive to the details of disorder. A temperature regime of the interacti ... [Phys. Rev. B 82, 075424 ] published .
We study the interference between the Fano and Kondo effects in a side-coupled double quantum dot system where one of the quantum dots couples to conduction-electron bath while the other dot only side couples to the first dot via antiferromagnetic (AF) spin-exchange coupling. We apply both the pertu ... [Phys. Rev. B 82, 085325 ] published .
Assuming diffusive carrier transport and employing an effective medium theory, we calculate the temperature dependence of bilayer graphene conductivity due to Fermi-surface broadening as a function of carrier density. We find that the temperature dependence of the conductivity depends strongly on th ... [Phys. Rev. B 82, 075423 ] published .
Terahertz (>1 THz) irradiation of pinched-off quantum point contacts (QPCs) generates a pronounced photo-current due to radiation-induced heating. This response is reproduced by a model of temperature-dependent transmission through a saddle potential, confirming its bolometric nature. ... [Appl. Phys. Lett. 97, 083109 (2010)] published Thu Aug 26, 2010.
Strong, long-range Coulomb interactions can lead to correlated motions of multiple charged particles, which can induce important many-body effects in semiconductors. The exciton states formed from correlated electronhole pairs have been studied extensively, but basic properties of multiple-exciton ... [Nature 466, 1089 (2010)] published Fri Aug 27, 2010.
A nonlocal quantum-mechanical model is employed to compute plasmonic excitations of graphene in the presence of an impurity potential. A full diagonalization of the polarization operator is performed, allowing the extraction of all its poles. It is demonstrated that impurities induce the formation o ... [Phys. Rev. B 82, 081411 ] published .
We show that patterned defects can be used to disrupt the sublattice symmetry of graphene so as to open up a band gap. This way of modifying graphene's electronic structure does not rely on external agencies, the addition of new elements or special boundaries. The method is used to predict a planar, ... [Phys. Rev. B 82, 073410 ] published .
A Reply to the Comment by Christopher R. Weinberger. ... [Phys. Rev. Lett. 105, 099602 ] published .
A Comment on the Letter by A. Dutta et al., Phys. Rev. Lett. 101, 115506 (2008). The authors of the Letter offer a Reply. ... [Phys. Rev. Lett. 105, 099601 ] published .
We study the rotation-dependent epitaxial relations between graphene nanoflake and the Si-terminated 4H-SiC(0001) substrate. Depending on the rotation angle between the nanoflake and substrate surface, we find that Si-C bonds formed between the C atoms in the nanoflake and Si atoms on the SiC surfac ... [Phys. Rev. B 82, 085434 ] published .
YO with particle sizes ranging from 5 nm to 1 [mu]m were studied at high pressure using x-ray diffraction and Raman spectroscopy techniques. Nanometer-sized YO particles are shown to be more stable than their bulk counterparts, and a grain size-dependent crystalline-amorphous transition was discove ... [Phys. Rev. Lett. 105, 095701 ] published .
Atomistic simulations are used to study the bending of rectangular graphene nanoribbons subjected to axial stress both for free boundary and supported boundary conditions. The shapes of the deformations of the buckled graphene nanoribbons, for small values of the stress, are sine waves where the num ... [Phys. Rev. B 82, 085432 ] published .
We investigate the influence of surface energy anisotropy on the dynamics of quantum dot growth by looking at the long-time dynamics of the morphological (Asaro-Tiller-Grinfeld) instability of a strained thin film driven by surface diffusion during growth and annealing. We derive a continuum model a ... [Phys. Rev. B 82, 085322 ] published .
Virtual Journal of Ultrafast ScienceVirtual Journal of Ultrafast Science
High-harmonic large-orbit gyrotrons require long-length operating cavities because of both a weak electron-wave coupling and relatively low electron currents. Since diffraction Q factors of such cavities are very high, a large fraction of the radiated power is dissipated in Ohmic losses. A sectioned ... [Phys. Plasmas 17, 073101 (2010)] published Thu Jul 8, 2010.
When an atom is electronically excited, it relaxes by emitting a photon or an electron. These carry essential information on the electronic structure of their emitter. However, if an atom is embedded in a chemical environment, another ultrafast non-radiative decay process called interatomic Coulomb ... [Nature Phys. 6, 508 (2010)] published Thu Jul 1, 2010.
A multiple-laser flash shadowgraphy system has been innovatively designed and developed to study the terminal effects of projectiles. The system has been designed based on modulated laser diodes operated at low voltage and current. In order to study the ballistics effects of small arms, an exposure ... [Opt. Eng. 49, 064303 (2010)] published Thu Jul 1, 2010.
Triggering rain on demand is an old dream of mankind, with a huge potential socio-economical benefit. To date, efforts have mainly focused on cloud-seeding using silver salt particles. We demonstrate that self-guided ionized filaments generated by ultrashort laser pulses are also able to induce wate ... [Nat. Photonics 4, 451 (2010)] published Tue Jul 6, 2010.
Photons as information carriers have the potential to meet the ever-increasing demands on bandwidth and information density in fields such as information and communication technology, biomedicine and computing. Organic semiconductors may be well-suited to such applications, thanks to their ability t ... [Nat. Photonics 4, 438 (2010)] published Tue Jul 6, 2010.
This paper demonstrates the embellishment of existing microfluidic devices with integrated three dimensional (3D) micronanostructures via femtosecond laser micronanofabrication, which, for the first time, proves two-photon photopolymerization (TPP) to be a powerful technology for chip functionalizat ... [Lab Chip 10, 1993 (2010)] published Thu Jul 15, 2010.
A new scheme to efficiently accelerate protons by a single linear polarized high-intensity ultrashort laser pulse using multiple ultrathin foils is proposed. The foils are stacked at a spacing comparable to their thickness and subsequently irradiated by the same laser pulse. The foil thicknesses are ... [Phys. Rev. E 82, 016405 ] published .
In this paper we report on the radiography of a shock-compressed target using laser produced proton beams. A low-density carbon foam target was shock compressed by long pulse high-energy laser beams. The shock front was transversally probed with a proton beam produced in the interaction of a high in ... [Phys. Rev. E 82, 016407 ] published .
Electrons and alpha particles injected midway between two ultrahigh intensity crossed laser beams of radial polarization are shown to be accelerated in vacuum to several gigaelectron volts and to have average energy gradients in excess of 150 GeV/m. A unique model of the crossing beams is suggested, ... [Phys. Rev. A 82, 013823 ] published .
We address spectral tunneling of walking spatial solitons in photorefractive media with nonlocal diffusion component of the nonlinear response and an imprinted shallow optical lattice. In contrast to materials with local nonlinearities, where solitons traveling across the lattice close to the Bragg ... [Phys. Rev. A 82, 013806 ] published .
The excitation of radiation by bunched electron beams propagating in miniature corrugated plasma channels is considered. It is shown that the rate at which power is radiated by a beam is characterized by impedance that depends on the properties of the channel. For experimentally obtainable parameter ... [Phys. Plasmas 17, 073112 (2010)] published Fri Jul 30, 2010.
New advances in fabrication of low-density high-Z-doped foams have opened new windows on understanding how materials that are not in local thermodynamic equilibrium (LTE) are heated and radiate. Simulations are discussed in this paper of the x-ray spectral emissions from laser-irradiated very low-de ... [Phys. Plasmas 17, 073111 (2010)] published Thu Jul 29, 2010.
High density energetic electrons that are created by intense laser plasma interactions drive MeV proton acceleration. The correlation between accelerated MeV protons and escaped electrons is experimentally investigated at laser intensities in the range of 1010 W/cm with S-polarization. Observed pro ... [Phys. Plasmas 17, 073110 (2010)] published Thu Jul 29, 2010.
The range of plasma parameters, where the efficient quasitransient backward Raman amplification (QBRA) of powerful laser pulses is possible, is determined for dense plasmas with multicharged ions. Approximate scalings that portray in a simple way the efficient QBRA range in multidimensional paramete ... [Phys. Plasmas 17, 073109 (2010)] published Tue Jul 27, 2010.
The interaction of intense extreme ultraviolet (XUV) laser pulses (lambda=32 nm, I=1010 W/cm) with small rare-gas clusters (Ar) is studied by quasiclassical molecular dynamics simulations. Our analysis supports a very general picture of the charging and heating dynamics in finite samples under shor ... [Phys. Rev. A 82, 013201 ] published .
We experimentally demonstrate the vortex solitons of four-wave mixing (FWM) in multi-level atomic media created by the interference patterns with superposing three or more waves. The modulation effect of the vortex solitons is induced by the cross-Kerr nonlinear dispersion due to atomic coherence in ... [Opt. Express 18, 10963 (2010)] published Wed Jul 7, 2010.
The collimating effect of self-generated magnetic fields on fast-electron transport in solid aluminium targets irradiated by ultra-intense, picosecond laser pulses is investigated in this study. As the target thickness is varied in the range of 25 [mu]m to 1.4 mm, the maximum energies of protons acc ... [New J. Phys. 12, 063018 (2010)] published Thu Jul 1, 2010.
An era of exploring the interactions of high-intensity, hard X-rays with matter has begun with the start-up of a hard-X-ray free-electron laser, the Linac Coherent Light Source (LCLS). Understanding how electrons in matter respond to ultra-intense X-ray radiation is essential for all applications. H ... [Nature 466, 56 (2010)] published Thu Jul 1, 2010.
The distance over which the charge state distribution evolves during the expansion of laser produced Sn plasma in vacuum is investigated experimentally. This distance is found to be less than 6 cm with a planar target irradiated by a 1.064 [mu]m laser at 8.3 x 10 W/cm but greater than 60 cm when a ... [Appl. Phys. Lett. 97, 041502 (2010)] published Fri Jul 30, 2010.
Advanced laser wakefield accelerators offer electron beams which could be useful for many applications. However, the problem of stabilizing the electron beam parameters has not been resolved yet. Here, we report the generation of a relativistic electron beam with a stabilized pointing angle of 2 mra ... [Appl. Phys. Express 3, 076401 (2010)] published Mon Jul 26, 2010.
Laser wakefield experiments present a unique challenge in measuring the resulting electron energy properties due to the large energy range of interest, typically several 100 MeV, and the large electron beam divergence and pointing jitter >1 mrad. In many experiments the energy resolution and accura ... [Rev. Sci. Instrum. 81, 073304 (2010)] published Wed Jul 21, 2010.
The one-dimensional expansion into vacuum of ion-electron plasma produced by laser ablation is investigated. The ions considered as an ideal fluid are governed by a fluid model where charge quasineutrality is assumed to prevail, while electron density follows a non-Maxwellian distribution. Showing t ... [Phys. Plasmas 17, 074501 (2010)] published Thu Jul 8, 2010.
The results of particle-in-cell simulations are reported which demonstrate that a short-wavelength (lambda<=0.5 [mu]m) short-pulse laser driver can produce much more intense ion beams than the commonly used long-wavelength (lambda~1 [mu]m) ones. In particular, such a driver allows for efficient ge ... [Phys. Plasmas 17, 073106 (2010)] published Thu Jul 22, 2010.
Detailed angle and energy resolved measurements of positrons ejected from the back of a gold target that was irradiated with an intense picosecond duration laser pulse reveal that the positrons are ejected in a collimated relativistic jet. The laser-positron energy conversion efficiency is ~2 x 10. ... [Phys. Rev. Lett. 105, 015003 ] published .
Focusing of a 15 MeV electron bunch by a plasma lens operated at the threshold of the underdense regime has been demonstrated. The strong, 1.7 cm focal length, plasma lens focused both transverse directions simultaneously and reduced the minimum area of the beam spot by a factor of 23. It is shown t ... [Phys. Plasmas 17, 073105 (2010)] published Wed Jul 21, 2010.
The modification of photon frequency shifting based on taking into account the nonlinear quantum electrodynamics vacuum properties in plasma is studied. Motion equations of a laser field propagating in a plasma are derived from the HeisenbergEuler Lagrangian density. It is found that besides the cla ... [Phys. Plasmas 17, 073103 (2010)] published Fri Jul 16, 2010.
Photon acceleration of a laser pulse occurs in a medium with a space and time-varying permittivity. Using Hamiltonian formulation, a theoretical study of the frequency upshift of a probe laser pulse, which is considered as a quasiphoton or test particle, propagating through an amplified plasma densi ... [Phys. Plasmas 17, 073102 (2010)] published Wed Jul 14, 2010.
Based on a relativistic fluid-Maxwell model, laser-induced plasma dynamics is investigated for relativistic periodic waves. Within a one-dimensional (1D) description, the AkhiezerPolovin model is applied to the existence of periodic, nonlinearly coupled electromagnetic and electrostatic waves, and t ... [Phys. Plasmas 17, 072102 (2010)] published Thu Jul 8, 2010.
Stimulated Raman side scattering of an ultrashort high power laser pulse is studied in experiments on laser wakefield acceleration. Experiments and simulations reveal that stimulated Raman side scattering occurs at the beginning of the interaction, that it contributes to the evolution of the pulse p ... [Phys. Rev. Lett. 105, 034801 ] published .
We put forward a new approach to generate stable, fully three-dimensional light bullets, which is based on the matching of the intrinsic material dispersion with a suitable effective diffraction. The matching is achieved in adequate waveguide arrays whose refractive index is periodically modulated a ... [Phys. Rev. Lett. 105, 033901 ] published .
We have analyzed the coupling of ultraintense lasers (at ~2 x 10 W/cm) with solid foils of limited transverse extent (~10 s of [mu]m) by monitoring the electrons and ions emitted from the target. We observe that reducing the target surface area allows electrons at the target surface to be reflecte ... [Phys. Rev. Lett. 105, 015005 ] published .
The spatiotemporal pulse dynamics of a high-power relativistic laser pulse interacting with an electron-positron-ion plasmas is investigated theoretically and numerically. The occurrence of pulse compression is studied. The dependence of the mechanism on the concentration of the background ions in e ... [Phys. Rev. E 82, 016402 ] published .
Removal rate, air shock, and ablative recoil pressure parameters were measured as a function of laser intensity I during nanosecond laser ablation of graphite. Surface vaporization of molten graphite at low intensities I<0.15 GW/cm was observed to transform into its near-critical phase explosion (i ... [Phys. Rev. E 82, 016404 ] published .
The impact of 1.064 [mu]m laser absorption depth on the heating and in-band (2% bandwidth) 13.5 nm extreme ultraviolet emissions in Sn plasmas is investigated experimentally and numerically. In-band emission lasting longer than the laser pulse and separation between the laser absorption and in-band ... [Appl. Phys. Lett. 96, 261501 (2010)] published Wed Jun 30, 2010.
Light propagation in distributed-feedback optical structures with gain or loss regions is shown to provide an accessible laboratory tool to visualize in optics the spectral properties of the one-dimensional Dirac equation with non-Hermitian interactions. Spectral singularities and [script P][script ... [Phys. Rev. Lett. 105, 013903 ] published .
A new scheme for low-frequency coherent anti-Stokes Raman scattering spectroscopy (CARS) using chirped femtosecond pulses is proposed and demonstrated. Two chirped broadband optical pulses created terahertz (THz) polarization in the sample and generated CARS signal. The chirped CARS signal was then ... [Appl. Phys. Express 3, 072401 (2010)] published Mon Jul 26, 2010.
We report observations and analysis of high harmonic generation driven by a superposition of fields at 1290 nm and 780 nm. These fields are not commensurate in frequency and the superposition leads to an increase in the yield of the mid-plateau harmonics of more than two orders of magnitude compared ... [Opt. Express 18, 6853 (2010)] published Wed Jul 7, 2010.
We present an analytical description of ultrashort femtosecond pumpprobe experiments and investigate the gain response of quantum dot (QD) semiconductor optical amplifiers. The calculation provides a full analytical solution of numerical studies to recent experiments in such structures (Gomis-Bresco ... [New J. Phys. 12, 063012 (2010)] published Thu Jul 1, 2010.
Ultra-fast responding and recovering CHOH sensors were prepared using nanoscale SnO hollow spheres with NiO-functionalized inner walls. The exceptional ultra-fast recovery characteristics were attributed to the catalytic surface reaction assisted by NiO at the inner shell. ... [Chem. Commun. 46, 5061 (2010)] published Tue Jul 6, 2010.
We study two-dimensional soliton-soliton vector pairs in media with self-focusing nonlinearities and defocusing cross interactions. The general properties of the stationary states and their stability are investigated. The different scenarios of instability are observed using numerical simulations. T ... [Phys. Rev. E 82, 016605 ] published .
Abstract not available. [Phys. Rev. Lett. 105, 049902 ] published .
A large-ratio stretcher for ultra-short pulses is proposed based on photonic crystal fiber (PCF). Through proper design of the PCF structure, we obtain over 300-nm wavelength range with flattened dispersion characteristics. Analysis indicates that 1-km of such fiber can broaden over 10,000 times for ... [Opt. Express 18, 12341 (2010)] published Wed Jul 7, 2010.
Multiple light spots can be generated by modulating the spatial phase distribution of laser beam with a spatial light modulator (SLM). In this paper, we demonstrate the fabrication of three-dimensional 1 x 4 splitter waveguides inside a glass by focusing multiple light spots of femtosecond (fs) la ... [Opt. Express 18, 12136 (2010)] published Wed Jul 7, 2010.
We demonstrated spectral compression of ultrashort soliton pulses in a wide wavelength region based on an adiabatic soliton spectral compression technique using a comb-profile fiber. The comb-profile fiber was carefully designed using numerical analysis and fabricated using a conventional single-mod ... [Opt. Express 18, 11700 (2010)] published Wed Jul 7, 2010.
By particle-in-cell simulation and analysis, we propose a plasma approach to generate a relativistic chirped pulse based on a laser-foil interaction. When two counterpropagating circularly polarized pulses interact with an overdense foil, the driving pulse (with a larger laser field amplitude) will ... [Phys. Rev. Lett. 105, 025001 ] published .
We experimentally demonstrate a general optical pump-probe technique to observe the spin Hall effect of light (SHEL) in an absorbing medium. In essence, a locally confined pump-induced modification of a material's absorptivity can effectively be used as an induced aperture allowing one to detect the ... [Phys. Rev. B 82, 045303 ] published .
We observe the complete dynamics of the propagation of very intense, femtosecond laser pulses in air under tight focusing conditions via direct imaging of the entire interaction zone. The whole life history of the focused pulses is then reconstructed by means of numerical simulations. We show that b ... [Phys. Rev. A 82, 013805 ] published .
We demonstrate the collinear generation of few-femtosecond ultraviolet and attosecond extreme ultraviolet pulses via a combination of third-harmonic and high harmonic generation in noble gases. The ultrashort coherent light bursts are produced by focusing a sub-1.5-cycle near-infrared/visible laser ... [Opt. Express 18, 9173 (2010)] published Wed Jul 7, 2010.
The large infrared lateral photovoltaic effect (LPE) based on semiconductor structures has been a challenge for a long time because the light in this region is hard to be absorbed. In this study, we report an unusual infrared laser induced LPE observed in sputtered CuO thin films. The maximum open-c ... [Opt. Express 18, 9113 (2010)] published Wed Jul 7, 2010.
We report a novel system for the accurate measurement of all polarization related parameters, including polarization mode dispersion and polarization dependent loss, using binary magneto-optic polarization rotators. By taking advantage of the binary nature of the rotators, we achieved unprecedented ... [Opt. Express 18, 6667 (2010)] published Wed Jul 7, 2010.
Accurate three-dimensional modelling of nonlinear pulse propagation within a gas-filled capillary is essential for understanding and improving the XUV yield in high harmonic generation. We introduce both a new model based on a multimode generalized nonlinear Schrodinger equation and a novel spatio-s ... [Opt. Express 18, 13279 (2010)] published Wed Jul 7, 2010.
We theoretically investigate the formation of filament and plasma channel in Ar gas by intense femtosecond pulses in the Bessel, truncated Bessel, and combination of two Gaussian modes. Through the numerical results obtained by solving the generalized nonlinear Schrodinger equation coupled with the ... [Opt. Express 18, 12923 (2010)] published Wed Jul 7, 2010.
We have recently developed a spectral re-shaping technique to simultaneously measure nonlinear refractive index and nonlinear absorption. In this technique, the information about the nonlinearities is encoded in the frequency domain, rather than in the spatial domain as in the conventional Z-scan me ... [Opt. Express 18, 12727 (2010)] published Wed Jul 7, 2010.
We report the experimental and numerical observation of step-like behavior of the high-intensity transmission deep inside the bandgap of a 1D photonic crystal. We show this to be a novel manifestation of the quantization of the soliton area, and derive an upper limit for the energy of the transmissi ... [Opt. Express 18, 12708 (2010)] published Wed Jul 7, 2010.
Planar hybrid metamaterial with different split ring resonators (SRR) structure dimensions are fabricated on silicon substrates by femtosecond (fs) laser micro-lens array (MLA) lithography and lift-off process. The fabricated metamaterial structures consist of: (a) uniform metamaterial with 4 SRRs a ... [Opt. Express 18, 12421 (2010)] published Wed Jul 7, 2010.
We report the development of a two-color Fourier domain Pump-Probe Optical Coherence Tomography (PPOCT) system. Tissue phantom experiments to characterize the system performance demonstrated imaging depths in excess of 725 [mu]m, nearly comparable to the base Optical Coherence Tomography system. PPO ... [Opt. Express 18, 12399 (2010)] published Wed Jul 7, 2010.
We show demodulation and demultiplexing of multi-channel WDM differential phase-shift-keying (DPSK) signals operating simultaneously at 10 Gb/s and 40 Gb/s using a 1 x 4 wavelength selective switch. We achieve error-free performance for four channels equally spaced by 100 GHz propagated over an 85 k ... [Opt. Express 18, 11657 (2010)] published Wed Jul 7, 2010.
We experimentally realize ultrafast all-optical switching in the 1.5-[mu]m spectral region using cross-phase modulation inside a 5-mm long silicon waveguide. Modulation depths of up to 90% and switching window durations ~1 ps are achieved using 500-fs pump pulses with energies below 10 pJ. ... [Opt. Express 18, 11514 (2010)] published Wed Jul 7, 2010.
We present a broadband vibrational sum frequency generation (BB-VSFG) scheme using a novel ps visible pulse shape. We generate the fs IR pulse via standard procedures and simultaneously generate an `inverted' time-asymmetric narrowband ps visible pulse via second harmonic generation in the pump depl ... [Opt. Express 18, 11483 (2010)] published Wed Jul 7, 2010.
We propose a method to control the harmonic process by a mid-IR modulated polarization gating for the effective generation of an ultra-broadband supercontinuum in the neutral rare-gas media. Using a mid-IR polarization gating pulse modulated by a weaker 800-nm linearly polarized pulse, the ionizatio ... [Opt. Express 18, 11308 (2010)] published Wed Jul 7, 2010.
In this paper, we propose a saturable absorber (SA) device consisting on an in-fiber micro-slot inscribed by femtosecond laser micro fabrication, filled by a dispersion of Carbon Nanotubes (CNT). Due to the flexibility of the fabrication method, efficient and simple integration of the mode-locking d ... [Opt. Express 18, 11008 (2010)] published Wed Jul 7, 2010.
We report on the existence and stability of solitons in a defect embedded in a square optical lattice based on a photorefractive crystal with focusing saturable nonlinearity. These solitons exist in different bandgaps due to the change of defect intensity. For a positive defect, the solitons only ex ... [Opt. Express 18, 10956 (2010)] published Wed Jul 7, 2010.
A novel and simple method is presented to generate a tunable high-repetition-rate pulse train based on dual-mode self-injection locking of a Fabry-Perot laser diode (FP-LD). Two fiber Bragg gratings (FBGs) are used in the experiment as feedback components. The two self-injection-locked modes evolve ... [Opt. Eng. 49, 074201 (2010)] published Thu Jul 8, 2010.
The frequency-angular spectrum of the supercontinuum accompanying the filamentation of femtosecond laser pulses in KU-1 fused quartz at various wavelengths has been experimentally and numerically investigated. The splitting effect of divergent conical-emission radiation of the supercontinuum into di ... [J. Opt. Technol. 77, 463 (2010)] published Wed Jul 28, 2010.
This article discusses questions of how the pulse width of a femtosecond fiber laser, its spectrum, and the envelope of its spectrum vary when the pulse passes through single-mode and multimode quartz optical fibers about 1 m long. ... [J. Opt. Technol. 77, 297 (2010)] published Wed Jul 28, 2010.
We describe some experimental aspects required for the implementation of a few-order high-harmonic source for coherent diffractive imaging in the extreme-ultraviolet region. Polychromatic high-angle diffractive images have been successfully processed for both periodic and aperiodic inorganic samples ... [J. Appl. Phys. 108, 023106 (2010)] published Mon Jul 26, 2010.
Ultrabroadband terahertz generation up to 200 THz has been demonstrated using a 5 fs Ti:sapphire laser and a 4-N,N-dimethylamino-4-N-methyl-stilbazolium tosylate (DAST) crystal. The high-frequency components beyond 100 THz are much stronger than those generated using conventional electro-optic cryst ... [Appl. Phys. Lett. 97, 021105 (2010)] published Wed Jul 14, 2010.
We propose a scheme to generate isolated sub-100-as pulses with 30-fs lasers. Our model is based on high-order harmonic generation from a helium atom irradiated by a two-color femtosecond laser field, in which the driving and the control fields are linearly polarized and the polarization angle betwe ... [Phys. Rev. A 82, 013827 ] published .
We analyzed the amplification effect of orthogonally polarized pulse trapping in birefringent fibers both experimentally and numerically. Trapped pulses were amplified over a wide wavelength range of 1650-1800 nm accompanying the red-shift. The maximum effective gain was 26 dB for a 140 m-long low b ... [Opt. Express 18, 7323 (2010)] published Wed Jul 7, 2010.
We test two-dimensional TPSA of biphoton light emitted via ultrafast spontaneous parametric down-conversion (SPDC) using the effect of group-velocity dispersion in optical fibres. Further, we apply this technique to demonstrate the engineering of biphoton spectral properties by acting on the pump pu ... [Opt. Express 18, 12915 (2010)] published Wed Jul 7, 2010.
The polarization state of the white light produced by a femtosecond laser pulse through a water cell is investigated. The depolarization of the white light was found to be induced by magnification of the polarization perturbation in the incident light which is caused by the focus lens. Cross-phase m ... [Opt. Express 18, 12581 (2010)] published Wed Jul 7, 2010.
This work proposes a simple model of pulse Laguerre-Gaussian Beams (LGBs) by chopping the incident continuous wave LGB into ultrashort pulse. The pulse LGBs are expanded into a series of LGBs with the same angular quantum number (AQN), whose expansion coefficients show the time-varying and propagati ... [Opt. Express 18, 12104 (2010)] published Wed Jul 7, 2010.
We systematically study the characteristics of the Cherenkov second-harmonic generation in periodically poled lithium niobate by femtosecond pulses. A relatively high conversion efficiency is obtained and what we believe to be a new different explanation is proposed that nonlinearities in the domain ... [J. Opt. Soc. Am. B 27, 1475 (2010)] published Thu Jul 15, 2010.
We report on the energy exchange between femtosecond laser filaments in air. A traveling plasma grating formed at the intersection of the filaments is proposed to explain the energy transfer. In this moving plasma grating mediated mechanism the laser energy transfers from the lower frequency pulse t ... [Phys. Rev. Lett. 105, 055003 ] published .
We theoretically investigate the supercontinuum generation (SCG) on the basis of modulational instability (MI) in liquid-core photonic crystal fibers (LCPCF) with CS-filled central core. The effect of saturable nonlinearity of LCPCF on SCG in the femtosecond regime is studied using an appropriately ... [Phys. Rev. A 82, 013825 ] published .
We calculate the four-wave-mixing signal of excitons generated at k=k+k-k by two pulsed entangled photon pairs (k, k) and (k, k), where all four modes are chronologically ordered. Entangled photons offer an unusual combination of bandwidths and temporal resolution not possible by classical beams. Co ... [Phys. Rev. A 82, 013820 ] published .
For a quantum system with broken parity symmetry, selection rules cannot hold and cyclic transition structures are generated. With these loop transitions we discuss how to achieve inversionless gain of the probe field by properly setting the control and auxiliary fields. Possible implementations of ... [Phys. Rev. A 82, 013808 ] published .
We study quantum compression and decompression of light pulses that carry quantum information using a photon-echo quantum memory technique with controllable inhomogeneous broadening of an isolated atomic absorption line. We investigate media with differently broadened absorption profiles, transverse ... [Phys. Rev. A 82, 012309 ] published .
By using continuous-wave (CW)stimulated Raman scattering inside a high-finesse cavity, we generate three CW spectral components covering about one octave of optical bandwidth. We investigate the mutual coherence of these three beams by studying phase-dependent second harmonic generation. From the hi ... [Phys. Rev. A 82, 011805 ] published .
Scattering of light at a distribution of scatterers is an intrinsically cooperative process, which means that the scattering rate and the angular distribution of the scattered light are essentially governed by bulk properties of the distribution, such as its size, shape, and density, although local ... [Phys. Rev. A 82, 011404 ] published .
Time-multiplexed optical line-by-line pulse shaping with specific application to rapid update radio-frequency (RF) waveform generation is modeled. The effects of fundamental pulse shaping parameters on generated RF waveforms are numerically analyzed. Experimental and theoretical results are compared ... [Opt. Express 18, 9366 (2010)] published Wed Jul 7, 2010.
For a suspended core nanofiber, the holey region is expected to be as large as possible to propagate the light at wavelengths as long as possible. Additionally, a large holey region is significant for its applications in sensors. However, the fabrication of nanofiber with large holey region is still ... [Opt. Express 18, 9088 (2010)] published Wed Jul 7, 2010.
We report a compact all-fiber high-energy fiber laser that consists of a laser oscillator and a compression section. The laser oscillator generates the pulses with high energy and large chirp. The compression section is made of a piece of standard single-mode fiber that dechirps the chirped pulses. ... [Opt. Express 18, 8847 (2010)] published Wed Jul 7, 2010.
We investigate the effects of pulse duration on optical trappingwith high repetition rate ultrashort pulsed lasers, through Lorentz-Mietheory, numerical simulation, and experiment. Optical trapping experimentsuse a 12 femtosecond duration infrared pulsed laser, with the trappingmicroscope's temporal ... [Opt. Express 18, 7554 (2010)] published Wed Jul 7, 2010.
Spatiotemporal self-focusing in nonlinear lossy media pushes ultrashort pulses towards a universal, non-solitary and non-conical light bullet wave state defined by the medium solely, and characterized by maximum energy losses. Its stationary propagation relies on a balance between nonlinear losses a ... [Opt. Express 18, 7376 (2010)] published Wed Jul 7, 2010.
A system for supercontinuum generation by using a photonic crystal fiber within a synchronously pumped ring cavity is presented. The feedback led to an interaction of the generated supercontinuum with the following femtosecond laser pulses and thus to the formation of a nonlinear oscillator. The non ... [Opt. Express 18, 7190 (2010)] published Wed Jul 7, 2010.
Tunable narrowband THz waveforms were generated from laser induced gas plasma using shaped optical pulses. Square wave phase patterns were fed to a spatial light modulator. The frequency and amplitude of the square wave phase were used as parameters to tailor the terahertz waveforms. The dependence ... [Opt. Express 18, 7038 (2010)] published Wed Jul 7, 2010.
We report on the fabrication of sub-wavelength nanostructures on the surface of AsS chalcogenide glasses by appropriately controlling the irradiation condition of single-beam direct femtosecond laser writing. Nanogratings with a period of 180 nm were realized by multipulse irradiation. More importan ... [Opt. Express 18, 6885 (2010)] published Wed Jul 7, 2010.
We derive the spectral dependence of the non-linear susceptibility of any order, generalizing the common form of Sellmeier equations. This dependence is fully defined by the knowledge of the linear dispersion of the medium. This finding generalizes the Miller formula to any order of non-linearity. I ... [Opt. Express 18, 6613 (2010)] published Wed Jul 7, 2010.
A scheme to realize all-optical Boolean logic functions AND, XOR and NOT using semiconductor optical amplifiers with quantum-dot active layers is studied. nonlinear dynamics including carrier heating and spectral hole-burning are taken into account together with the rate equations scheme. Results sh ... [Opt. Express 18, 6417 (2010)] published Wed Jul 7, 2010.
The modulation bandwidth of quantum well nanoLED and nanolaser devices is calculated from the laser rate equations using a detailed model for the Purcell enhanced spontaneous emission. It is found that the Purcell enhancement saturates when the cavity quality-factor is increased, which limits the ma ... [Opt. Express 18, 11230 (2010)] published Wed Jul 7, 2010.
Here the authors report a novel optical second harmonic generation (SHG) measurement that allows carrier motion in solids to be probed directly. By catching nonlinear polarization induced in the solids by coupling with incident electromagnetic waves (laser beam) and dc electric field from moving car ... [J. Vac. Sci. Technol. B 28, C5F12 (2010)] published Tue Jul 27, 2010.
The fastest known operation of all-optical flip-flop memory was experimentally demonstrated using a 980-nm polarization bistable vertical-cavity surface-emitting laser (VCSEL). Operating conditions of the input signal power and the frequency detuning to achieve the fast optical memory operation were ... [Opt. Express 18, 12362 (2010)] published Wed Jul 7, 2010.
By means of micro-structural and optical characterization of the Yb:Nb:RbTiOPO crystal, we demonstrated that the broad emission band of Yb in these crystals is due to the large splitting of the ytterbium ground state only, and not to a complex multisite occupation by the ytterbium ions in the crysta ... [Opt. Express 18, 7228 (2010)] published Wed Jul 7, 2010.
Photonic ultra-wideband (UWB) pulses are generated by direct current modulation of a semiconductor optical amplifier (SOA) section of an SOA-integrated sampled grating distributed Bragg reflector (SGDBR) laser. Modulation responses of the SOA section of the laser are first simulated with a microwave ... [Opt. Express 18, 7219 (2010)] published Wed Jul 7, 2010.
We apply a pump- and probe-scheme to coplanar stripline circuits to investigate the photocurrent response of GaAs photoswitches in time and space. We find a displacement current pulse, as reported earlier. We interpret a time-delayed second pulse as a transport current. In a time-of-flight analysis ... [Appl. Phys. Lett. 96, 261110 (2010)] published Thu Jul 1, 2010.
The interplay between light and matter is the basis of many fundamental processes and various applications. Harnessing lightmatter interactions in principle allows operation of solid state devices under new physical principles: for example, the a.c. optical Stark effect (OSE) has enabled coherent q ... [Nature 466, 91 (2010)] published Thu Jul 1, 2010.
We studied the photocarrier decay dynamics of Mn-doped CdS nanocrystals (NCs) coated with a ZnS shell layer by femtosecond pumpprobe transient absorption spectroscopy. At low excitation intensities, the decay dynamics of photocarriers is determined by energy transfer from electronhole pairs in C ... [J. Phys. Soc. Jpn. 79, 063710 (2010)] published Thu Jul 1, 2010.
We present a broadband (460 - 980 nm) analysis of the nonlinear absorption processes in bulk ZnO, a large-bandgap material with potential blue-to-UV photonic device applications. Using an optical parametric amplifier we generated tunable 1-kHz repetition rate laser pulses and employed the Z-scan tec ... [Opt. Express 18, 9628 (2010)] published Wed Jul 7, 2010.
We demonstrate amorphization in a GeSbTe (GST) thin film through a nonthermal process by femtosecond electronic excitation. Amorphous recording marks were formed by irradiation with a single femtosecond pulse, and were confirmed to be recrystallized by laser thermal annealing. Scanning electron micr ... [Appl. Opt. 49, 3470 (2010)] published Wed Jul 7, 2010.
Effects of high pressure in a range of up to 1.7 GPa on ultrafast energy relaxation of LDS698 (CHNOCl) molecules in solution have experimentally been illustrated by a method of femtosecond time-resolved absorption spectroscopy. The rates of the intramolecular and intermolecular energy relaxations sh ... [Opt. Express 18, 6863 (2010)] published Wed Jul 7, 2010.
Using high-intensity femtosecond laser pulses, we create a novel surface pattern that transforms regular silicon to superwicking. Due to the created surface structure, water sprints vertically uphill in a gravity defying way. Our study of the liquid motion shows that the fast self-propelling motion ... [Opt. Express 18, 6455 (2010)] published Wed Jul 7, 2010.
We report on numerical and experimental characterization of the performance of a fiber link optimized for the delivery of sub-100-fs laser pulses at 1550 nm over several meters of fiber. We investigate the power handling capacity of the link, and demonstrate all-fiber delivery of 1-nJ pulses over a ... [Opt. Express 18, 6978 (2010)] published Wed Jul 7, 2010.
Femtosecond spectral hole burning experiments were performed on InAs/GaAs quantum dots to investigate the influence of high excitation intensities. The observation of additional spectral holes, as well as distinct absorption line broadening are both attributed to two-photon absorption processes. The ... [Appl. Phys. Lett. 97, 011903 (2010)] published Wed Jul 7, 2010.
We use time-resolved photoluminescence spectroscopy and photoluminescence excitation spectroscopy to measure the valence band parameters of hexagonal wurtzite InP nanowires. The A exciton emission and excitation energy is observed at 1.504 eV as expected. Excitation spectra show that the B and C hol ... [Appl. Phys. Lett. 97, 023106 (2010)] published Wed Jul 14, 2010.
Hole spin relaxation dynamics in CdTe/CdSe core-shell nanocrystals are measured by an ultrafast polarization transient grating technique. Photoexcited charge separation in type II structures suppresses the electron-hole exchange interaction and the hole spin relaxation time constant is found to incr ... [Phys. Rev. Lett. 105, 046601 ] published .
We propose a semiclassical model for femtosecond laser-induced demagnetization due to spin-polarized excited electron diffusion in the superdiffusive regime. Our approach treats the finite elapsed time and transport in space between multiple electronic collisions exactly, as well as the presence of ... [Phys. Rev. Lett. 105, 027203 ] published .
We report on band-dependent quasiparticle dynamics in BaKFeAs (T=37 K) measured using ultrafast pump-probe spectroscopy. In the superconducting state, we observe two distinct relaxation processes: a fast component whose decay rate increases linearly with excitation density and a slow component with ... [Phys. Rev. Lett. 105, 027005 ] published .
A coherent phonon mode with frequency corresponding to the first mini Brillouin-zone edge stop gap is observed in ultrafast pump-probe measurements on a doped semiconductor superlattice structure. It is proposed that the optical detection of the mode is facilitated by interactions with the free carr ... [Phys. Rev. B 82, 041302 ] published .
With an interest in pulsed laser deposition and remote spectroscopy techniques, we explore here the potential of laser pulses temporally tailored on ultrafast time scales to control the expansion and the excitation degree of various ablation products including atomic species and nanoparticulates. Ta ... [Phys. Rev. B 82, 035430 ] published .
When a hybrid system consisting of a metallic nanoparticle and a semiconductor quantum dot interacts with a coherent light source (laser beam) the coherence generated in the quantum dot can significantly renormalize the plasmonic field. In this paper we study the impacts of such coherent-plasmonic p ... [Phys. Rev. B 82, 035413 ] published .
Red shift and splitting of surface plasmon band in absorption spectra of copper nanoparticles incorporated in silica matrix have been observed under irradiation by intense femtosecond laser pulse with power density 1010 W/cm. These phenomena are interpreted as a result of change of dielectric const ... [Phys. Rev. B 82, 033401 ] published .
We study the excitation dynamics of a single molecular nanomagnet by static and pulsed magnetic fields. Based on a stability analysis of the classical magnetization dynamics we identify analytically the fields parameters for which the energy is stochastically pumped into the system in which case the ... [Phys. Rev. B 82, 014418 ] published .
We have investigated the electroabsorption of aligned micelle-wrapped single-walled carbon nanotubes induced by intense terahertz (THz) pulses by using THz-pump and optical-probe spectroscopy at room temperature. The electroabsorption signal is enhanced at exciton resonances near the optical communi ... [Appl. Phys. Lett. 97, 041111 (2010)] published Tue Jul 27, 2010.
We report the observation of spin-lattice coupling in multiferroic YMnO by femtosecond near-infrared pump and probe spectroscopy. A coherent 31 GHz acoustic phonon was detected above the magnetic ordering temperature, and a higher frequency coherent mode was observed in the antiferromagnetic phase. ... [Appl. Phys. Lett. 97, 031914 (2010)] published Thu Jul 22, 2010.
A picosecond pump-probe technique is used to reveal the optoacoustic response of a single micrometric carbon fiber. The signature of the intrinsic geometric scattering resulting from acoustic reflections at free surface of the cylindrical cavity is contained in the signals. The fiber transverse elas ... [Appl. Phys. Lett. 97, 031901 (2010)] published Mon Jul 19, 2010.
We report a time-resolved propagating spin wave spectroscopy for FeNi film. We show that the amplitude of the spin-wave packet depends on the direction of magnetization and that its phase can be controlled by the polarity of pulsed magnetic field for the excitation. The nonreciprocal emission of spi ... [Appl. Phys. Lett. 97, 022508 (2010)] published Thu Jul 15, 2010.
Spatially indirect excitons in a coupled quantum well structure were studied by means of polarization and time-resolved photoluminescence. A strong degree of circular polarization (>50%) in emission was achieved when the excitation energy was tuned into resonance with the direct exciton state. The i ... [Appl. Phys. Lett. 97, 011104 (2010)] published Thu Jul 8, 2010.
Terahertz time domain spectroscopy has been used to study low frequency confined acoustic phonons of silver nanoparticles embedded in poly(vinyl alcohol) matrix in the spectral range of 0.12.5 THz. The real and imaginary parts of the dielectric function show two bands at 0.60 and 2.12 THz attributed ... [J. Chem. Phys. 133, 014502 (2010)] published Fri Jul 2, 2010.
We investigate the quasiparticle relaxation and low-energy electronic structure in undoped SrFeAs exhibiting spin-density wave (SDW) ordering using optical pump-probe femtosecond spectroscopy. A remarkable critical slowing down of the quasiparticle relaxation dynamics at the SDW transition temperatu ... [Phys. Rev. B 82, 012505 ] published .
We study the quantum critical behavior of the XY spin chain with multisite interaction by means of a fidelity susceptibility (FS) calculation. The key ingredients (e.g., finite-size scaling behavior, universality principle) of the quantum criticality near the critical point are investigated carefull ... [Phys. Rev. A 82, 012308 ] published .
Terahertz (THz) signals can be generated by the periodic motion of ballistic electron bunches inside a quantum well cavity surrounded by two asymmetric resonant tunneling structure implemented in an InAlAs/InGaAs heterostructure. The electron bunches are produced in an adjacent active quantum well b ... [J. Appl. Phys. 108, 026103 (2010)] published Tue Jul 27, 2010.
Ultrafast dynamics of genuine magneto-optical recording across ferrimagnetic compensation points is demonstrated in GdFeCo films using time-resolved polar Kerr spectroscopy combined with a laser-synchronized sinusoidal alternating magnetic field which can reinitialize irreversible initial magnetizat ... [J. Appl. Phys. 108, 023902 (2010)] published Fri Jul 16, 2010.
Nonequilibrium carrier recombination in highly excited epitaxial layers of 4HSiC and free standing 3CSiC was analyzed numerically and studied experimentally by the time-resolved free carrier absorption (FCA) technique. The measurement setup combined interband carrier excitation by a picosecond laser ... [J. Appl. Phys. 108, 023705 (2010)] published Tue Jul 27, 2010.
We apply ultrafast single shot interferometry to determine the pressure and density of argon shocked from up to 7.8 GPa static initial pressure in a diamond anvil cell. This method enables the observation of thermodynamic states distinct from those observed in either single shock or isothermal compr ... [J. Appl. Phys. 108, 023511 (2010)] published Tue Jul 27, 2010.
Spectrally-, polarization-, and time-resolved photoluminescence (PL) experiments have been performed on 2.5 nm thick m-plane single InGaN quantum wells. It has been found that PL decay is mainly determined by nonradiative recombination through several types of recombination centers, while PL rise is ... [J. Appl. Phys. 108, 023101 (2010)] published Fri Jul 16, 2010.
Recombination of minority carriers in heavily doped n-InP wafers has been investigated using spectral and time-resolved photoluminescence at different temperatures. Studies of the transmitted luminescence were enabled by the partial transparency of the samples due to the MossBurstein effect. Tempora ... [J. Appl. Phys. 108, 013101 (2010)] published Thu Jul 1, 2010.
This study explores the effects of both Oxygen and temperature on the carrier dynamics of isoelectronic ZnSeO (x=0.027 and 0.053) semiconductors using photoluminescence (PL) and time-resolved PL spectroscopy. We find that the Kohlrausch law is highly consistent with the complex decay traces induced ... [Appl. Phys. Lett. 97, 041909 (2010)] published Thu Jul 29, 2010.
A full micromagnetic model and a simplified one-dimensional analytical model are used to investigate the domain wall dynamics driven by an oblique magnetic field. Both models show that the Walker breakdown [N. L. Schryer and L. R. Walker, J. Appl. Phys. 45, 5406 (1974)] can occur at two distinct fie ... [Appl. Phys. Lett. 97, 032507 (2010)] published Fri Jul 23, 2010.
We demonstrate near-field nanohole patterning using a Mie resonance, small size parameter particle for nanofabrication technology regardless of substrate's refractive index. Maximal enhancement factor and nearly smallest spot diameter among the same size dielectric particles are simultaneously obtai ... [Appl. Phys. Lett. 96, 261103 (2010)] published Tue Jun 29, 2010.
We propose and demonstrate an ultrafast all-optical method to couple light to surface plasmon polaritons on planar gold films. By interfering two 150 fs, 810 nm pulses we excite a transient grating in the temperature of the free electrons of the metal, resulting in a grating in the dielectric functi ... [Phys. Rev. Lett. 105, 017402 ] published .
We investigate the formation of diversiform micro-/nano-structures in High-Pressure High-Temperature (HPHT) synthetic single-crystal diamond by tight-focusing 200 fs regeneratively amplified Ti: Sapphire laser pulses centered at lambda = 800 nm. Ablated samples of synthetic single crystal nanodiamon ... [Opt. Express 18, 13122 (2010)] published Wed Jul 7, 2010.
Subterahertz radiation emitted from a variety of short rectangular-, square-, and disk-shaped mesas of intrinsic Josephson junctions fabricated from a BiSrCaCuO single crystal was studied from the observed I-V characteristics, far-infrared spectra, and spatial radiation patterns. In all cases, the r ... [Phys. Rev. Lett. 105, 037005 ] published .
We present an analysis of the time evolution of a highly excited silicon substrate after partial absorption of a femtosecond soft x-ray pulse. The detailed time-dependent thermoelastic behavior of the substrate in terms of the displacements u(r,t) is derived for time delays for which the usual local ... [Rev. Sci. Instrum. 81, 073102 (2010)] published Thu Jul 8, 2010.
The study of chemical reactions on the molecular (femtosecond) timescale typically uses pump laser pulses to excite molecules and subsequent probe pulses to interrogate them. The ultrashort pump pulse can excite only a small fraction of molecules, and the probe wavelength must be carefully chosen t ... [Nature 466, 604 (2010)] published Thu Jul 29, 2010.
Ever since the first lasers were built over 40 years ago, chemists and physicists have been attempting to exploit them as tools for controlling the outcome of chemical reactions. Over the last decade this dream has become a reality. The most successful approaches have employed learning algorithms to ... [Phys. Chem. Chem. Phys. 12, 8948 (2010)] published Thu Jul 29, 2010.
The autoionization of atomic fragments after core-to-Rydberg excitations in N has been studied using high-resolution electron spectroscopy. Doppler profiles are clearly observed on atomic autoionization peaks and show dependence on the symmetries of the excited states. It is demonstrated that inform ... [New J. Phys. 12, 063030 (2010)] published Thu Jul 1, 2010.
We investigate the momentum and energy distributions of the two electrons in multiphoton double ionization of He by intense attosecond xuv pulses, based on a two-dimensional model. Two different patterns of the momentum distributions are identified, corresponding to the uncorrelated and correlated c ... [Opt. Express 18, 8976 (2010)] published Wed Jul 7, 2010.
We experimentally investigate the high harmonic generation (HHG) from CH molecules and Xe atoms in a two-color field (using the 800nm laser and the tunable laser with the longer wavelength from 1500nm to 1900nm), and observe that the longer wavelength component can destructively suppress the HHG fro ... [Opt. Express 18, 11664 (2010)] published Wed Jul 7, 2010.
We have measured high-order harmonic generation spectra of D, N, and CO by mixing orthogonally polarized 800 and 400 nm laser fields. The intensity of the high-harmonic spectrum is modulated as we change the relative phase of the two pulses. For randomly orientated molecules, the phase of the intens ... [Phys. Rev. Lett. 105, 053003 ] published .
We present an interferometric pump-probe technique for the characterization of attosecond electron wave packets (WPs) that uses a free WP as a reference to measure a bound WP. We demonstrate our method by exciting helium atoms using an attosecond pulse (AP) with a bandwidth centered near the ionizat ... [Phys. Rev. Lett. 105, 053001 ] published .
We present time-resolved studies and Fourier transform spectroscopy of inner-shell excited states undergoing Auger decay and doubly excited autoionizing states, utilizing coherent extreme-ultraviolet (XUV) radiation continua. Series of states spanning a range of ~4 eV are excited simultaneously. An ... [Phys. Rev. Lett. 105, 043902 ] published .
High-order harmonic generation from hydrogenlike muonic atoms exposed to ultraintense high-frequency laser fields is studied. Systems of low nuclear-charge number Z are considered where a nonrelativistic description applies. By comparing the radiative response for different isotopes, we demonstrate ... [Phys. Rev. A 82, 013418 ] published .
We study theoretically the electron wave packet generated by an attosecond pulse train (APT) which is probed with a time-delayed infrared (IR) laser pulse. The APT creates an excited state and a continuum electron wave packet. By ionizing the excited state with an IR, a delayed new continuum electro ... [Phys. Rev. A 82, 013409 ] published .
It has been shown that control over the design of single- or multimode-transparency windows can be achieved by control-probe quantum interferometry using two delayed phase-locked ultrashort pulses. We have investigated how single- or multimode-transparency windows can be designed by eliminating the ... [Phys. Rev. A 82, 013404 ] published .
We investigate double ionization of argon dimers in high-intensity ultrashort Ti:sapphire laser pulses. We are able to identify several strong-field excitation pathways of the dimer that terminate in atomic ion pairs from a Coulomb explosion. The explosion starts from two-site double-ionized dimers ... [Phys. Rev. A 82, 013413 ] published .
Photodissociation of acetylene has been studied using the H-atom Rydberg tagging time-of-flight technique at two excitation wavelengths (148.35 and 151.82 nm) in the vacuum ultraviolet region. Product translational energy distributions have been obtained from the H-atom time-of-flight spectra. Exper ... [J. Chem. Phys. 133, 014307 (2010)] published Wed Jul 7, 2010.
We have characterized the vibrational predissociation (VP) of the NeBr van der Waals complex using time- and frequency-resolved pump-probe spectroscopy. After exciting Br within the complex to a vibrational level 16<=nu<=23 in the B state, we follow the flow of halogen vibrational energy to the van ... [J. Chem. Phys. 133, 014305 (2010)] published Wed Jul 7, 2010.
The generation of highly charged Xe ions up to q=24 is observed in Xe clusters embedded in helium nanodroplets and exposed to intense femtosecond laser pulses (lambda=800 nm). Laser intensity resolved measurements show that the high-q ion generation starts at an unexpectedly low threshold intensity ... [Phys. Rev. Lett. 105, 053401 ] published .
In a regular, flexible chain of Rydberg atoms, a single electronic excitation localizes on two atoms that are in closer mutual proximity than all others. We show how the interplay between excitonic and atomic motion causes electronic excitation and diatomic proximity to propagate through the Rydberg ... [Phys. Rev. Lett. 105, 053004 ] published .
We investigate the possibility to monitor the dynamics of autoionizing states in real-time and control the yields of different ionization channels in helium by simulating extreme ultraviolet (XUV) pump IR-probe experiments focused on the N=2 threshold. The XUV pulse creates a coherent superposition ... [Phys. Rev. Lett. 105, 053002 ] published .
We investigate how various versions of the molecular strong-field approximation (MSFA) agree with the experiment by Grasbon et al. [Phys. Rev. A 63, 041402(R) (2001)], in which the suppression of the ionization yield in the low-energy spectrum of the O molecule, compared to the spectrum of its compa ... [Phys. Rev. A 82, 015401 ] published .
Triply differential probability rates for electron-positron pair creation in laser-nucleus collisions, calculated within the S-matrix approach, are investigated as functions of the nuclear recoil. Pronounced enhancements of differential probability rates of multiphoton pair production are found for ... [Phys. Rev. A 82, 013420 ] published .
We investigate the coherent control of nonresonant two-photon excitation and (2+1) photon ionization processes from the time-dependent perspective. To this end, we have solved the time-dependent Schrodinger equation for a hydrogen atom interacting with an ultraviolet laser field. Results are obtaine ... [Phys. Rev. A 82, 013414 ] published .
We show that a single femtosecond optical frequency comb may be used to induce two-photon transitions between molecular vibrational levels to form ultracold molecules (e.g., KRb). The phase across an individual pulse in the pulse train is sinusoidally modulated with a carefully chosen modulation amp ... [Phys. Rev. A 82, 013407 ] published .
On the basis of the Floquet formalism, the ionization mechanisms of atomic hydrogen in circularly and linearly polarized intense laser fields are discussed. By using the complex scaling method in the velocity gauge, the pole positions of the scattering-matrix on the complex quasienergy Riemann surfa ... [Phys. Rev. A 82, 013402 ] published .
This article presents a detailed analysis of the Kalpha x-ray spectra of Si induced by 11.4 MeV/u Ca projectiles penetrating a low-density SiO aerogel target measured with high spectral and spatial resolution at the UNILAC accelerator at GSI-Darmstadt. The low-density material used in the experiment ... [Phys. Rev. A 82, 012703 ] published .
Using three-dimensional classical ensembles, we have investigated the internuclear distance dependence of nonsequential double ionization (NSDI) of H molecules by an 800 nm, 1 x 10 W/cm laser pulse. For the internuclear distance R ranging from 2 to 12 a.u., the NSDI of H provides rich correlation pa ... [Opt. Express 18, 9064 (2010)] published Wed Jul 7, 2010.
We study the effect of pure dephasing on a two-level system in strong coupling in the nonlinear regime with the single mode of a cavity. The photoluminescence spectrum of the cavity has a robust tendency to display triplet structures, instead of the expected Jaynes-Cummings pairs of doublets at the ... [Opt. Express 18, 7002 (2010)] published Wed Jul 7, 2010.
An ultrafast mechanism belonging to the family of interatomic Coulombic decay (ICD) phenomena is proposed. When two excited species are present, an ultrafast energy transfer can take place bringing one of them to its ground state and ionizing the other one. It is shown that if large homoatomic clust ... [Phys. Rev. Lett. 105, 043004 ] published .
The alignment dependence of the ionization behavior of H exposed to intense ultrashort laser pulses is investigated on the basis of solutions of the full time-dependent Schrodinger equation within the fixed-nuclei and dipole approximation. The total ionization yields as well as the energy-resolved e ... [Phys. Rev. A 82, 011403 ] published .
We have measured the two-site double ionization of argon dimers by ultrashort laser pulses leading to fragmentation into two singly charged argon ions. Contrary to the expectations from a pure Coulomb explosion following rapid removal of one electron from each of the atoms, we find three distinct pe ... [Phys. Rev. A 82, 013412 ] published .
We have observed the simultaneous inner-shell absorption of two extreme-ultraviolet photons by a Xe atom in an experiment performed at the short-wavelength free electron laser facility FLASH. Photoelectron spectroscopy permitted us to unambiguously identify a feature resulting from the ionization of ... [Phys. Rev. Lett. 105, 013001 ] published .
We have determined the multiphoton ionization and dissociation pathways of D with the simultaneous irradiation of the high-order harmonic fields and the low-order harmonic fields of Ti:sapphire laser pulses in the visible-vacuum ultraviolet region with the aid of a nonlinear Fourier-transform spectr ... [Phys. Rev. A 82, 013421 ] published .
We demonstrate the creation of vibrational wave packets on multiple electronic states of a molecule via strong-field ionization. Furthermore, we show that the relative contribution of the different electronic states depends on the shape of the laser pulse which launches the wave packets. ... [Phys. Rev. A 82, 011402 ] published .
Photosynthetic antenna complexes capture and concentrate solar radiation by transferring the excitation to the reaction center that stores energy from the photon in chemical bonds. This process occurs with near-perfect quantum efficiency. Recent experiments at cryogenic temperatures have revealed t ... [Proc. Natl. Acad. Sci. U.S.A. 107, 12766 (2010)] published Mon Jul 26, 2010.
We present a time-resolved absorption study on the light-induced generation of reversible linkage NO isomers in single crystals of Na[Fe(CN)NO]2HO using laser pulses of 160 fs width. Using the pump wavelength lambda = 500 nm the singletsinglet A-->E excitation induces the NO rotation by about 90 deg ... [Phys. Chem. Chem. Phys. 12, 9029 (2010)] published Thu Jul 29, 2010.
The ring-puckering vibration in cyclopentene was studied by rotational time-resolved femtosecond degenerate four-wave mixing (fs DFWM) spectroscopy. The fs DFWM spectra of cyclopentene were measured both in a supersonic expansion and in a gas cell at room temperature. The room temperature fs DFWM sp ... [Phys. Chem. Chem. Phys. 12, 8190 (2010)] published Thu Jul 15, 2010.
We report on studies of the recently synthesized compound (TPC1) with a promising potential use in dye-sensitized solar cells. We used steady-state as well as femtosecond (fs) to nanosecond (ns) time-resolved emission techniques to understand its behaviour under different conditions of solvation and ... [Phys. Chem. Chem. Phys. 12, 8098 ] published .
In order to collect detailed information on the interaction mechanism between fluorescent thiourea derivatives and anions, 9-[4-(trifluoromethyl)phenylthioureidomethyl]anthracene (1) and the corresponding 10-cyanoanthracene derivative (2) were synthesized and investigated in DMSO and MeCN by using a ... [Phys. Chem. Chem. Phys. 12, 8062 ] published .
The ultrafast relaxation of 1-iodonaphthalene, with particular attention to the dissociation channels, has been studied by time-resolved femtosecond pumpprobe mass spectrometry following excitation at 267 and 317 nm. The measured transients for the parent ion and the isobaric fragments, iodine and n ... [Phys. Chem. Chem. Phys. 12, 7988 ] published .
By applying femtosecond pumpprobe spectroscopy to a substituted quinquethiophene molecule in solution, we observe in the time domain the coherent torsional dynamics that drives planarization of the excited state. Our interpretation is based on numerical modeling of the ground and excited state poten ... [Phys. Chem. Chem. Phys. 12, 7917 ] published .
To design more effective CIEEL (chemically initiated electron exchange luminescence) systems demands a complete picture of the dynamics of the chemiluminescence, which is often a challenge. In this work, photoluminescence of the methyl m-oxybenzoate anion the authentic emitter of AMPPD (3-[2-spiroa ... [Phys. Chem. Chem. Phys. 12, 6789 (2010)] published Fri Jul 2, 2010.
In this paper, we consider the dynamics of a molecular system subjected to external pumping by a light source. Within a completely quantum mechanical treatment, we derive a general formula, which enables us to assess the effects of different light properties on the photo-induced dynamics of excitati ... [New J. Phys. 12, 065044 (2010)] published Thu Jul 1, 2010.
Electronic coherence has been shown to persist in the FennaMatthewsOlson (FMO) antenna complex from green sulfur bacteria at 77 K for at least 660 fs, several times longer than the typical lifetime of a coherence in a dynamic environment at this temperature. Such long-lived coherence was proposed to ... [New J. Phys. 12, 065042 (2010)] published Thu Jul 1, 2010.
It has been suggested that excitation transport in photosynthetic light-harvesting complexes features speedups analogous to those found in quantum algorithms. Here we compare the dynamics in these light-harvesting systems to the dynamics of quantum walks, in order to elucidate the limits of such qua ... [New J. Phys. 12, 065041 (2010)] published Thu Jul 1, 2010.
Soret band lifetimes of the free-base tetraphenylporphine (HTPP) and Cu(ii) tetraphenylporphine (CuTPP) at 408 nm have been directly measured with femtosecond (fs) resolution using the fluorescence-upconversion technique for the first time, giving tau = 68 15 and 63 15 fs, respectively, in benzene ... [Chem. Commun. 46, 5572 (2010)] published Mon Jul 26, 2010.
Circulating tumor cells in the bloodstream are sensitive indicators for metastasis and disease prognosis. Circulating cells have usually been monitored via extraction from blood, and more recently in vivo using free-space optics; however, long-term intravital monitoring of rare circulating cells rem ... [J. Biomed. Opt. 15, 047004 (2010)] published Mon Jul 26, 2010.
Since the birth of Dolly as the first mammal cloned from a differentiated cell, somatic cell cloning has been successful in several mammalian species, albeit at low success rates. The highly invasive mechanical enucleation step of a cloning protocol requires sophisticated, expensive equipment and co ... [J. Biomed. Opt. 15, 046006 (2010)] published Wed Jul 21, 2010.
Ultrafast, time-resolved investigations of acid-base neutralization reactions have recently been performed using systems containing the photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) and various Bronsted bases. Two conflicting neutralization mechanisms have been formulated by ... [J. Chem. Phys. 133, 044108 (2010)] published Fri Jul 23, 2010.
Recent two-dimensional infrared (2D-IR) experiments on a short peptide 3-helix in chloroform solvent [E. H. G. Backus et al., J. Phys. Chem. B 113, 13405 (2009)] revealed an intriguing temperature dependence of the homogeneous line width, which was interpreted in terms of a dynamical transition of t ... [J. Chem. Phys. 133, 034512 (2010)] published Tue Jul 20, 2010.
Femtosecond laser spectroscopies are used to examine the electronic structures of two proteins found in the phycobilisome antenna of cyanobacteria, allophycocyanin (APC) and C-phycocyanin (CPC). The wave function composition involving the pairs of phycocyanobilin pigments (i.e., dimers) found in bot ... [J. Chem. Phys. 133, 024507 (2010)] published Wed Jul 14, 2010.
The present work is devoted to the description of a nonperturbative treatment of anharmonic effect and mode-mode coupling taking place in molecular vibrational systems. The information is obtained from the four-wave-mixing signal detected in the usual photon-echo phase-matched direction, termed 4WM ... [Phys. Rev. A 82, 013423 ] published .
Recently, femtosecond laser pulses have been utilized for the targeted introduction of genetic matter into mammalian cells. This rapidly expanding and developing novel optical technique using a tightly focused laser light beam is called phototransfection. Extending previous studies [Stevenson et al. ... [J. Biomed. Opt. 15, 041507 (2010)] published Tue Jul 6, 2010.
Measuring distribution of dissolved oxygen in biological tissue is of prime interest for cancer diagnosis, prognosis, and therapy optimization. Tumor hypoxia indicates poor prognosis and resistance to radiotherapy. Despite its major clinical significance, no current imaging modality provides direct ... [J. Biomed. Opt. 15, 040501 (2010)] published Wed Jul 21, 2010.
Steady-state and nanosecond time-resolved spectroscopies are performed to investigate the interaction between CdSe quantum dots (QDs) and mesotetraphenylporphyrin (TPP) photosensitizers under two-photon excitation with 800-nm femtosecond laser pulses. The luminescent intensity and lifetime of the QD ... [J. Micro/Nanolith. MEMS MOEMS 9, 031003 (2010)] published Fri Jul 2, 2010.
The coherent third order optical response of molecular aggregates with fluctuating frequencies, couplings, and transition dipole moments is studied. We derived stochastic nonlinear exciton equations (SNEEs) by combining the quasiparticle picture of excitons with the path integral over stochastic bat ... [J. Chem. Phys. 133, 014102 (2010)] published Fri Jul 2, 2010.
A tabletop ultra-bright, debris-free femtosecond-laser-driven cluster-based plasma soft X-ray source, which emits more than $10^{12}$ photons/(sr$\cdot$pulse) in the spectral range 110 nm within a $4\pi$ sr solid angle was developed. Using such source in combination with a high dynamic range LiF ... [Jpn. J. Appl. Phys. 49, 06GK03 (2010)] published Thu Jul 1, 2010.
Carrier-envelope phase stabilization has opened an avenue towards achieving frequency metrology with unprecedented precision and optical pulse generation on the previously inaccessible attosecond timescale. Recently, sub-100-as pulse generation has been demonstrated, approaching the timescale of the ... [Nat. Photonics 4, 462 (2010)] published Tue Jul 6, 2010.
We propose a method to generate an isolated attosecond (as) pulse in combination with a chirped fundamental laser field (5 fs, 800 nm) and a subharmonic laser field (12 fs, 1600 nm). It is shown that, for the case of the chirped parameter beta=0.25, not only is the efficiency of the extended harmoni ... [Phys. Rev. A 82, 013411 ] published .
We present a combined theoretical and experimental study of spatiotemporal propagation effects in terahertz (THz) generation in gases using two-color ionizing laser pulses. The observed strong broadening of the THz spectra with increasing gas pressure reveals the prominent role of spatiotemporal res ... [Phys. Rev. Lett. 105, 053903 ] published .
High density (25 x 10 cm) self-organized InGaN/GaN quantum dots were grown by plasma-assisted molecular beam epitaxy. Room temperature photoluminescence shows that the quantum dots have strong emission ranging from 430 to 524 nm. The internal quantum efficiency of dots emitting at 500 nm was determ ... [Appl. Phys. Lett. 97, 011103 (2010)] published Wed Jul 7, 2010.
We demonstrated a 7.36 nm Ni-like samarium soft-x-ray laser, pumped by 36 J of a neodymium:glass chirped-pulse amplification laser. Double-pulse single-beam non-normal-incidence pumping was applied for efficient soft-x-ray laser generation. In this case, the applied technique included a single-optic ... [Phys. Rev. A 82, 013803 ] published .
We successfully fabricated a cascadable film-type single-wall carbon nanotube (SWNT) saturable absorber coated on aromatic polyamide film, in which the saturable absorption effect can be controlled with the number of films. A conductive polymer P3HT (poly-3-hexylthiophene) was adopted to obtain a un ... [Opt. Express 18, 9712 (2010)] published Wed Jul 7, 2010.
We present a 1.07 [mu]m all-fiber femtosecond soliton laser employing a film-type saturable absorber with a P3HT (poly-3-hexylthiophene) incorporated SWNT coated on polyimide film. We optimized the laser cavity as a dispersion-managed soliton laser with photonic crystal fiber (PCF) as an anomalous d ... [Opt. Express 18, 11223 (2010)] published Wed Jul 7, 2010.
A frequency-stabilized light source emitting at 556 nm is realized by frequency doubling a 1112 nm laser, which is phase locked to a fiber-based optical frequency comb. The 1112 nm laser is either an ytterbium (Yb)-doped distributed feedback fiber laser or a master-slave laser system that uses an ex ... [J. Opt. Soc. Am. B 27, 1388 (2010)] published Thu Jul 15, 2010.
An optically induced fast wavelength shift is demonstrated in a standard middle infrared (MIR) quantum cascade laser (QCL) by illuminating the front facet with a femtosecond (fs) near infrared (NIR) laser, allowing fast optical frequency modulation (FM) for free space optical communication (FSOC) an ... [Appl. Phys. Lett. 97, 011102 (2010)] published Wed Jul 7, 2010.
We have electro-optically sliced the output light of a commercial Coherent Evolution Nd:YLF laser to pump a kilohertz repetition rate nanosecond dye laser system. Simple and highly adjustable, this laser system can easily be used for initial state preparation for ultrafast systems as well as high re ... [Rev. Sci. Instrum. 81, 073111 (2010)] published Wed Jul 28, 2010.
We have generated single-transverse-mode optical pulses with 100 W peak power and 3 ps duration at 1 GHz repetition from a blue-violet GaInN mode-locked laser diode (MLLD) and a semiconductor optical amplifier (SOA) without the use of any pulse compression. The generation of clean optical pulses wit ... [Appl. Phys. Lett. 97, 021101 (2010)] published Mon Jul 12, 2010.
Detailed analysis of the tilted-pulse-front pumping scheme used for ultrashort THz pulse generation by optical rectification of femtosecond laser pulses is presented. It is shown that imaging errors in a pulse-front-tilting setup consisting of a grating and a lens can lead to a THz ... [Opt. Express 18, 12311 (2010)] published Wed Jul 7, 2010.
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