May 22, 2013 ? A revelation of how photoreceptive cells in the eye distinguish between different light sources could pave the way for a novel class of optical devices.
Millions of years of evolution have molded our eyes into highly sensitive optical detectors, surpassing even many human-made devices. Now, Leonid Krivitsky and his co-workers at the A*STAR Data Storage Institute and the A*STAR Institute of Medical Biology, Singapore, have shown that the photoreceptor cells found in the retina are even sensitive to the statistical properties of light. This ability could be harnessed in 'bioquantum' interfaces, a novel class of optical devices that use biological systems to detect the quantum nature of light.
Light comprises discrete bundles of energy known as photons. A 40-Watt light bulb, for example, creates more than 1019 (a one followed by 19 zeros) visible photons every second. Nevertheless, attenuated sources that generate light pulses containing just a few photons are also useful. In such ultralow-intensity light pulses, the statistical distribution of photons emitted in a single pulse depends on the light source.
Warm light sources such as light-bulb filaments generate photons in bunches. Lasers, in contrast, create photons randomly -- each is emitted independently of the next. Krivitsky and his co-workers experimentally demonstrated that rod photoreceptor cells in the eye can distinguish between pulses of light from either a laser or a thermal light based only on these differing distributions. "Showing that such cells can assess photon statistics provides hope for accessing the quantum properties of light using biodetectors," says Krivitsky.
Krivitsky and his team trapped a photoreceptor cell from a frog on the end of a suction pipette. Then they fired green-light laser pulses at the cell through an optical fiber. The same device could also imitate a thermal light source when they placed a rotating disk of ground glass and an aperture into the beam path.
They observed that rhodopsin molecules in the cell absorbed the incoming photons, which generated an ion current. The researchers amplified and measured this current as the average number of photons in each light pulse increased. They noticed a much sharper increase in detected current for the laser light than the pseudothermal pulses. This is because, while the average photon number is the same, an individual pseudothermal pulse was more likely to have a low number of photons. The photon distribution of the laser pulses, on the other hand, was much narrower.
The two types of photon emitters investigated in these experiments are examples of 'classical' light sources. "The next step is to investigate quantum light, such as pulses with a fixed number of photons," notes Krivitsky.
The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute and the Institute of Medical Biology
After previously investing in the company, Google has now acquired Makani Power, a green energy startup that is currently building airborne wind turbines. The acquisition was first reported in Brad Stone’s Businessweek story about Google X, and judging from Stone’s story, the team will join Google X. Google invested $10 million in the Alameda, Calif.-based company in 2006 and another $5 million in 2008. As far as we can see, this also marks the first time Google has acquired a company specifically for its Google X skunkworks. Stone reports that Google CEO Larry Page approved the acquisition, but as Google X’s director Astro Teller notes, Page said that X “could have the budget and the people to go do this, but that we had to make sure to crash at least five of the devices in the near future.? The company was founded by Saul Griffith and Don Montague, a former World Cup windsurfer. The price of the acquisition was not disclosed. Google has confirmed this acquisition and provided us with the following statement from Astro Teller, Google X’s “Captain of Moonshots”: Creating clean energy is one of the most pressing issues facing the world, and Google for years has been interested in helping to solve this problem. ?Makani Power?s technology has opened the door to a radical new approach to wind energy. ?They?ve turned a technology that today involves hundreds of tons of steel and precious open space into a problem that can be solved with really intelligent software. ?We?re looking forward to bringing them into Google[x]. Makani says it hopes that this acquisition will provide it with “the resources to accelerate our work to make wind energy cost competitive with fossil fuels.”?The acquisition comes just a week after the company completed the first autonomous flight of its Wing 7 prototype. Here is how TechCrunch columnist Matylda Czarnecka described the project back in 2012: The Makani Airborne Wind Turbines, which resemble mini airplanes, are launched when wind speeds reach 3.5 meters per second. Rotors on each blade help propel it into orbit, and double as turbines once airborne. The blades are tethered to the ground with a cord that delivers power to throw them into the sky and receives energy generated by the turbines to be sent to the grid-connected ground station.
Contact: Jade Boyd jadeboyd@rice.edu 713-348-6778 Rice University
Arranging nanoparticles in geometric patterns allows for control of light with light
HOUSTON -- (May 21, 2013) -- Rice University scientists have unveiled a robust new method for arranging metal nanoparticles in geometric patterns that can act as optical processors that transform incoming light signals into output of a different color. The breakthrough by a team of theoretical and applied physicists and engineers at Rice's Laboratory for Nanophotonics (LANP) is described this week in the Proceedings of the National Academy of Sciences.
Rice's team used the method to create an optical device in which incoming light could be directly controlled with light via a process known as "four-wave mixing." Four-wave mixing has been widely studied, but Rice's disc-patterning method is the first that can produce materials that are tailored to perform four-wave mixing with a wide range of colored inputs and outputs.
"Versatility is one of the advantages of this process," said study co-author Naomi Halas, director of LANP and Rice's Stanley C. Moore Professor in Electrical and Computer Engineering and a professor of biomedical engineering, chemistry, physics and astronomy. "It allows us to mix colors in a very general way. That means not only can we send in beams of two different colors and get out a third color, but we can fine-tune the arrangements to create devices that are tailored to accept or produce a broad spectrum of colors."
The information processing that takes place inside today's computers, smartphones and tablets is electronic. Each of the billions of transistors in a computer chip uses electrical inputs to act upon and modify the electrical signals passing through it. Processing information with light instead of electricity could allow for computers that are both faster and more energy-efficient, but building an optical computer is complicated by the quantum rules that light obeys.
"In most circumstances, one beam of light won't interact with another," said LANP theoretical physicist Peter Nordlander, a co-author of the new study. "For instance, if you shine a flashlight at a wall and you cross that beam with the beam from a second flashlight, it won't matter. The light that comes out of the first flashlight will pass through, independent of the light from the second.
"This changes if the light is traveling in a 'nonlinear medium,'" he said. "The electromagnetic properties of a nonlinear medium are such that the light from one beam will interact with another. So, if you shine the two flashlights through a nonlinear medium, the intensity of the beam from the first flashlight will be reduced proportionally to the intensity of the second beam."
The patterns of metal discs LANP scientists created for the PNAS study are a type of nonlinear media. The team used electron-beam lithography to etch puck-shaped gold discs that were placed on a transparent surface for optical testing. The diameter of each disc was about one-thousandth the width of a human hair. Each was designed to harvest the energy from a particular frequency of light; by arranging a dozen of the discs in a closely spaced pattern, the team was able to enhance the nonlinear properties of the system by creating intense electrical fields.
"Our system exploits a particular plasmonic effect called a Fano resonance to boost the efficiency of the relatively weak nonlinear effect that underlies four-wave mixing," Nordlander said. "The result is a boost in the intensity of the third color of light that the device produces."
Graduate student and co-author Yu-Rong Zhen calculated the precise arrangement of 12 discs that would be required to produce two coherent Fano resonances in a single device, and graduate student and lead co-author Yu Zhang created the device that produced the four-wave mixing -- the first such material ever created.
"The device Zhang created for four-wave mixing is the most efficient yet produced for that purpose, but the value of this research goes beyond the design for this particular device," said Halas, who was recently named a member of the National Academy of Sciences for her pioneering research in nanophotonics. "The methods used to create this device can be applied to the production of a wide range of nonlinear media, each with tailored optical properties."
###
High-resolution IMAGES are available for download at:
http://news.rice.edu/wp-content/uploads/2013/05/0520-FANO-Mix-lg.jpg
CAPTION: Physicists and engineers from Rice's Laboratory for Nanophotonics have unveiled a robust new method for arranging metal nanoparticles in geometric patterns that can act as optical processors that transform incoming light signals into output of a different color.
CAPTION: By arranging optically tuned gold discs in a closely spaced pattern, Rice University scientists created intense electrical fields and enhanced the nonlinear optical properties of the system. Here a computer model displays the plasmonic interactions that give rise to the intense fields.
CAPTION: Gold discs tuned to capture the energy from two incoming beams of light can produce output of a third color. Here a computer animation shows how the electromagnetic wave (red=positive, blue=negative) from the incoming light propagates through the system as a series of plasmonic waves.
CREDIT: Yu-Rong Zhen/Rice University
A copy of the PNAS paper is available at:
http://www.pnas.org/cgi/doi/10.1073/pnas.1220304110
This release can be found online at:
http://news.rice.edu/2013/05/21/rice-unveils-method-for-tailoring-optical-processors/
[ | E-mail | Share ]
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AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Contact: Jade Boyd jadeboyd@rice.edu 713-348-6778 Rice University
Arranging nanoparticles in geometric patterns allows for control of light with light
HOUSTON -- (May 21, 2013) -- Rice University scientists have unveiled a robust new method for arranging metal nanoparticles in geometric patterns that can act as optical processors that transform incoming light signals into output of a different color. The breakthrough by a team of theoretical and applied physicists and engineers at Rice's Laboratory for Nanophotonics (LANP) is described this week in the Proceedings of the National Academy of Sciences.
Rice's team used the method to create an optical device in which incoming light could be directly controlled with light via a process known as "four-wave mixing." Four-wave mixing has been widely studied, but Rice's disc-patterning method is the first that can produce materials that are tailored to perform four-wave mixing with a wide range of colored inputs and outputs.
"Versatility is one of the advantages of this process," said study co-author Naomi Halas, director of LANP and Rice's Stanley C. Moore Professor in Electrical and Computer Engineering and a professor of biomedical engineering, chemistry, physics and astronomy. "It allows us to mix colors in a very general way. That means not only can we send in beams of two different colors and get out a third color, but we can fine-tune the arrangements to create devices that are tailored to accept or produce a broad spectrum of colors."
The information processing that takes place inside today's computers, smartphones and tablets is electronic. Each of the billions of transistors in a computer chip uses electrical inputs to act upon and modify the electrical signals passing through it. Processing information with light instead of electricity could allow for computers that are both faster and more energy-efficient, but building an optical computer is complicated by the quantum rules that light obeys.
"In most circumstances, one beam of light won't interact with another," said LANP theoretical physicist Peter Nordlander, a co-author of the new study. "For instance, if you shine a flashlight at a wall and you cross that beam with the beam from a second flashlight, it won't matter. The light that comes out of the first flashlight will pass through, independent of the light from the second.
"This changes if the light is traveling in a 'nonlinear medium,'" he said. "The electromagnetic properties of a nonlinear medium are such that the light from one beam will interact with another. So, if you shine the two flashlights through a nonlinear medium, the intensity of the beam from the first flashlight will be reduced proportionally to the intensity of the second beam."
The patterns of metal discs LANP scientists created for the PNAS study are a type of nonlinear media. The team used electron-beam lithography to etch puck-shaped gold discs that were placed on a transparent surface for optical testing. The diameter of each disc was about one-thousandth the width of a human hair. Each was designed to harvest the energy from a particular frequency of light; by arranging a dozen of the discs in a closely spaced pattern, the team was able to enhance the nonlinear properties of the system by creating intense electrical fields.
"Our system exploits a particular plasmonic effect called a Fano resonance to boost the efficiency of the relatively weak nonlinear effect that underlies four-wave mixing," Nordlander said. "The result is a boost in the intensity of the third color of light that the device produces."
Graduate student and co-author Yu-Rong Zhen calculated the precise arrangement of 12 discs that would be required to produce two coherent Fano resonances in a single device, and graduate student and lead co-author Yu Zhang created the device that produced the four-wave mixing -- the first such material ever created.
"The device Zhang created for four-wave mixing is the most efficient yet produced for that purpose, but the value of this research goes beyond the design for this particular device," said Halas, who was recently named a member of the National Academy of Sciences for her pioneering research in nanophotonics. "The methods used to create this device can be applied to the production of a wide range of nonlinear media, each with tailored optical properties."
###
High-resolution IMAGES are available for download at:
http://news.rice.edu/wp-content/uploads/2013/05/0520-FANO-Mix-lg.jpg
CAPTION: Physicists and engineers from Rice's Laboratory for Nanophotonics have unveiled a robust new method for arranging metal nanoparticles in geometric patterns that can act as optical processors that transform incoming light signals into output of a different color.
CAPTION: By arranging optically tuned gold discs in a closely spaced pattern, Rice University scientists created intense electrical fields and enhanced the nonlinear optical properties of the system. Here a computer model displays the plasmonic interactions that give rise to the intense fields.
CAPTION: Gold discs tuned to capture the energy from two incoming beams of light can produce output of a third color. Here a computer animation shows how the electromagnetic wave (red=positive, blue=negative) from the incoming light propagates through the system as a series of plasmonic waves.
CREDIT: Yu-Rong Zhen/Rice University
A copy of the PNAS paper is available at:
http://www.pnas.org/cgi/doi/10.1073/pnas.1220304110
This release can be found online at:
http://news.rice.edu/2013/05/21/rice-unveils-method-for-tailoring-optical-processors/
[ | E-mail | Share ]
?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Editor's note:?Glenn Solomon?is a partner with GGV Capital. Some of his recent investments include Pandora, Successfactors, Isilon, Domo, Square, Zendesk, Quinstreet, and Nimble Storage. Stanford-born and Seattle-based Tableau Software (DATA) enjoyed a tremendous debut on the public markets on Friday, closing on its first day of trading at over $50/share, up over 60 percent from its $31/share IPO price. The company raised over $250 million through the sale of approximately 14 percent?of the company, and its enterprise value now sits at approximately $2.5 billion.
Last week, when Smith + Gill Architects unveiled its design for Imperial Tower, which will become Mumbai?s tallest building (by a lot!), their description of the project confounded many critics. ?The building,? the architects explained, ?is designed to confuse the wind.? Huh? Curious to know exactly what that meant, I got in touch with the Gordon Gill, one half of the Chicago-based office.
WASHINGTON (AP) ? One more time, with feeling! The Republican-led House voted yet again Thursday to repeal President Barack Obama's health care law, knowing full well that won't stop it.
Only months away from the rollout of coverage for uninsured Americans, it was the 37th attempt in a little more than two years by House Republicans to eliminate, defund or partly scale back the Affordable Care Act. The Democratic-led Senate and the president will simply ignore the House action, which came on a virtual party line vote, 229-195.
But in a Congress where spin often trumps legislation, Republicans see a political advantage to keeping the pressure up as the administration tries to get all the moving parts of the law finally working.
Starting this fall, uninsured people who can't get coverage through their jobs will be able to sign up for government-subsidized insurance that takes effect Jan. 1. The rollout promises to be bumpy because about half the states are still resisting the law, and congressional Republicans won't provide the administration with funds it says are needed for a smooth implementation.
Democrats said the House vote was a pointless exercise. They noted that the ACA ? as the law is known ? has been upheld by the Supreme Court, and millions are already receiving some benefits, from young adults able to stay on a parent's insurance until age 26, to seniors on Medicare whose high prescription drug bills have been reduced.
Democratic leader Nancy Pelosi of California said the vote was "a waste of the public's time."
Rep. George Miller, D-Calif., called it an "obsession ... bordering on the absurd."
But Republicans see a soft target in a costly program that continues to divide the country.
They're hoping that implementation problems next year will help the GOP take control of the Senate in the midterm congressional elections and build on its House majority. Part of the political strategy behind Thursday's vote was to give freshmen Republicans a chance to vote on full repeal of what they dismiss as "Obamacare."
"Republicans will continue to work to scrap the law in its entirety so we can focus on patient-centered reforms that lower costs and protect jobs," said House Speaker John Boehner, R-Ohio.
What that alternative would look like, no one really knows, because Republicans have not presented a plan of their own since Obama's law was debated in Congress more than three years ago.
Boehner said a GOP approach would include medical malpractice reforms, risk pools for people with pre-existing medical problems, and letting individuals buy coverage from out-of-state insurers to spur competition. But nothing has been finalized.
Boehner also pointed out that not even Obama believes the health care law is perfect. On seven previous occasions GOP efforts to scale back parts of the law were eventually accepted by the president and signed into law. They included a Medicaid formula that would have allowed thousands of middle-class people to qualify for nearly free coverage, a long-term care insurance plan likely to go belly-up, and paperwork requirements protested by small businesses. The administration sees those as relatively minor changes.
The House debate got creative. Rep. Michele Bachmann, R-Minn., compared the health care law both to a looming iceberg and an impending train wreck. Bachmann said there was a point to holding another repeal vote. "It's our job to defend liberty," she said. "And that's why we have to end this horrible piece of legislation." Back home, her political operation teed up an ad to spread word of the vote and her role in it.
Three years after its passage, Americans remain divided over Obama's signature domestic policy achievement. Even the uninsured are confused about whether they will be helped. Many people who have coverage worry it will raise their costs and make it harder for them to see their doctors. Some of the law's underlying goals, such as a ban on insurers turning away people with pre-existing conditions, remain popular. However, the requirement that virtually all Americans carry coverage or face fines is still widely disliked.
Although health insurance premiums have not gone down, as Obama once promised, there's no evidence that the law is breaking the bank. Health care costs have been growing at historically low rates, providing a respite for government programs like Medicare and employer plans as well. Experts say most people with job-based health insurance are unlikely to see major impacts from the law next year.
Less certain is the outlook for people who buy their own coverage and for small businesses. The insurance industry says premiums in the individual market are likely go up by double digits in most states. The administration says part of the reason costs could go up is because the coverage will be more comprehensive. But many people will receive tax credits under the law to offset those costs. Still, the anxiety is building as the law's full implementation draws closer.
On one of its official Twitter accounts, the White House tweeted "It's. The. Law." adding the hashtag (hash)ObamaCareInThreeWords.
___
Associated Press writer Brian Bakst in St. Paul, Minn., contributed to this report.
May 14, 2013 ? An international team of scientists have revealed a new species of ichthyosaur (a dolphin-like marine reptile from the age of dinosaurs) from Iraq, which revolutionises our understanding of the evolution and extinction of these ancient marine reptiles.
The results, produced by a collaboration of researchers from universities and museums in Belgium and the UK and published today (May 15) in Biology Letters, contradict previous theories that suggest the ichthyosaurs of the Cretaceous period (the span of time between 145 and 66 million years ago) were the last survivors of a group on the decline.
Ichthyosaurs are marine reptiles known from hundreds of fossils from the time of the dinosaurs. "They ranged in size from less than one to over 20 metres in length. All gave birth to live young at sea, and some were fast-swimming, deep-diving animals with enormous eyeballs and a so-called warm-blooded physiology," says lead author Dr Valentin Fischer of the University of Liege in Belgium.
Until recently, it was thought that ichthyosaurs declined gradually in diversity through multiple extinction events during the Jurassic period. These successive events were thought to have killed off all ichthyosaurs except those strongly adapted for fast-swimming life in the open ocean. Due to this pattern, it has been assumed that ichthyosaurs were constantly and rapidly evolving to be ever-faster open-water swimmers; seemingly, there was no 'stasis' in their long evolutionary history.
However, an entirely new ichthyosaur from the Kurdistan region of Iraq substantially alters this view of the group. The specimen concerned was found during the 1950s by British petroleum geologists. "The fossil -- a well-preserved partial skeleton that consists of much of the front half of the animal -- wasn't exactly being treated with the respect it deserves. Preserved within a large, flat slab of rock, it was being used as a stepping stone on a mule track," says co-author Darren Naish of the University of Southampton. "Luckily, the geologists realized its potential importance and took it back to the UK, where it remains today," adds Dr Naish, who is based at the National Oceanography Centre, Southampton.
Study of the specimen began during the 1970s with ichthyosaur expert Robert Appleby, then of University College, Cardiff. "Robert Appleby recognised that the specimen was significant, but unfortunately died before resolving the precise age of the fossil, which he realised was critical," says Jeff Liston of National Museums Scotland and manager of the research project. "So continuation of the study fell to a new generation of researchers."
In the new study (which properly includes Appleby as an author), researchers name it Malawania anachronus, which means 'out of time swimmer'. Despite being Cretaceous in age, Malawania represents the last-known member of a kind of ichthyosaur long believed to have gone extinct during the Early Jurassic, more than 66 million years earlier. Remarkably, this kind of archaic ichthyosaur appears characterised by an evolutionary stasis: they seem not to have changed much between the Early Jurassic and the Cretaceous, a very rare feat in the evolution of marine reptiles.
"Malawania's discovery is similar to that of the coelacanth in the 1930s: it represents an animal that seems 'out of time' for its age. This 'living fossil' of its time demonstrates the existence of a lineage that we had never even imagined. Maybe the existence of such Jurassic-style ichthyosaurs in the Cretaceous has been missed because they always lived in the Middle-East, a region that has previously yielded only a single, very fragmentary ichthyosaur fossil," adds Dr Fischer.
Thanks to both their study of microscopic spores and pollen preserved on the same slab as Malawania, and to their several analyses of the ichthyosaur family tree, Fischer and his colleagues retraced the evolutionary history of Cretaceous ichthyosaurs. In fact, the team was able to show that numerous ichthyosaur groups that appeared during the Triassic and Jurassic ichthyosaur survived into the Cretaceous. It means that the supposed end of Jurassic extinction event did not ever occur for ichthyosaurs, a fact that makes their fossil record quite different from that of other marine reptile groups.
When viewed together with the discovery of another ichthyosaur by the same team in 2012 and named Acamptonectes densus, the discovery of Malawania constitutes a 'revolution' in how we imagine ichthyosaur evolution and extinction. It now seems that ichthyosaurs were still important and diverse during the early part of the Cretaceous. The final extinction of the ichthyosaurs -- an event that occurred about 95 million years ago (long before the major meteorite-driven extinction event that ended the Cretaceous) -- is now even more confusing than previously assumed.
After previously investing in the company, Google has now acquired Makani Power, a green energy startup that is currently building airborne wind turbines. The acquisition was first reported in Brad Stone’s Businessweek story about Google X, and judging from Stone’s story, the team will join Google X. Google invested $10 million in the Alameda, Calif.-based company in 2006 and another $5 million in 2008. As far as we can see, this also marks the first time Google has acquired a company specifically for its Google X skunkworks. Stone reports that Google CEO Larry Page approved the acquisition, but as Google X’s director Astro Teller notes, Page said that X “could have the budget and the people to go do this, but that we had to make sure to crash at least five of the devices in the near future.? The company was founded by Saul Griffith and Don Montague, a former World Cup windsurfer. The price of the acquisition was not disclosed. Google has confirmed this acquisition and provided us with the following statement from Astro Teller, Google X’s “Captain of Moonshots”: Creating clean energy is one of the most pressing issues facing the world, and Google for years has been interested in helping to solve this problem. ?Makani Power?s technology has opened the door to a radical new approach to wind energy. ?They?ve turned a technology that today involves hundreds of tons of steel and precious open space into a problem that can be solved with really intelligent software. ?We?re looking forward to bringing them into Google[x]. Makani says it hopes that this acquisition will provide it with “the resources to accelerate our work to make wind energy cost competitive with fossil fuels.”?The acquisition comes just a week after the company completed the first autonomous flight of its Wing 7 prototype. Here is how TechCrunch columnist Matylda Czarnecka described the project back in 2012: The Makani Airborne Wind Turbines, which resemble mini airplanes, are launched when wind speeds reach 3.5 meters per second. Rotors on each blade help propel it into orbit, and double as turbines once airborne. The blades are tethered to the ground with a cord that delivers power to throw them into the sky and receives energy generated by the turbines to be sent to the grid-connected ground station.![[ Back to EurekAlert! ]](http://www.eurekalert.org/images/back2e.gif){kind=small}
Public release date: 21-May-2013
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Editor's note:?Glenn Solomon?is a partner with GGV Capital. Some of his recent investments include Pandora, Successfactors, Isilon, Domo, Square, Zendesk, Quinstreet, and Nimble Storage. Stanford-born and Seattle-based Tableau Software (
