Researchers create new nanostructure that absorbs broad spectrum of light from all

first_img © 2011 PhysOrg.com (PhysOrg.com) — Researchers working at Cal Tech, have taken an idea first proposed by Koray Aydin, now at Northwestern and have created a new nanostructure that appears to be capable of absorbing light of any polarization and virtually any angle. The new “plasmonic” material has thus far shown it can convert light into heat, and holds promise for improving the efficiency of solar cells. The team, led by Harry Atwater has published their findings in Nature Communications. Citation: Researchers create new nanostructure that absorbs broad spectrum of light from all angles (2011, November 10) retrieved 18 August 2019 from https://phys.org/news/2011-11-nanostructure-absorbs-broad-spectrum-angles.html Solar power could get boost from new light absorption design More information: Broadband polarization-independent resonant light absorption using ultrathin plasmonic super absorbers, Nature Communications 2, Article number: 517 doi:10.1038/ncomms1528AbstractResonant plasmonic and metamaterial structures allow for control of fundamental optical processes such as absorption, emission and refraction at the nanoscale. Considerable recent research has focused on energy absorption processes, and plasmonic nanostructures have been shown to enhance the performance of photovoltaic and thermophotovoltaic cells. Although reducing metallic losses is a widely sought goal in nanophotonics, the design of nanostructured ‘black’ super absorbers from materials comprising only lossless dielectric materials and highly reflective noble metals represents a new research direction. Here we demonstrate an ultrathin (260 nm) plasmonic super absorber consisting of a metal–insulator–metal stack with a nanostructured top silver film composed of crossed trapezoidal arrays. Our super absorber yields broadband and polarization-independent resonant light absorption over the entire visible spectrum (400–700 nm) with an average measured absorption of 0.71 and simulated absorption of 0.85. Proposed nanostructured absorbers open a path to realize ultrathin black metamaterials based on resonant absorption. Researchers have been working hard for several years to improve the efficiency of solar panels, because doing so would drive down costs, which so far have not been enough to allow solar cells to compete with fossil fuels. The problem is that current solar cells are based on silicon which is somewhat expensive to manufacture. Efforts to reduce the amount used in solar cells have resulted in lower efficiencies, and so are not really viable. Now however, it appears a different way to approach the problem might be at hand. The new material created by the Cal Tech team, because it absorbs more light, could be laid over conventional solar panels making them far more efficient. This means the silicon in them could be made thinner and the cells would still be more efficient than what is currently available. All because the new material is able to absorb more of the light that strikes it due to a scattering effect that it causes.The new material is made of silver and is shaped into rows of trapezoids with a variety of bumps along the edges of various shapes and lengths to cause the light to bend in diverse ways. The result is a material that is able to absorb up to 70% of light across the visible spectrum. To make it polarization independent, they laid an identical sheet of the material across the first at a 90° angle.By absorbing more light, the new material is able to convert the same amount of light shining on the material into more heat than other materials. The next step is in figuring out how to convert that extra absorbed light to more electricity and to do so with different kinds of materials, and that is just what Aydin and Atwater are working on together. Journal information: Nature Communications Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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Sony hints at holodeck future with captivating videos

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. The videos were made to advertise the immersive effect buyers will find if they will only rent movies for download from the Playstation store; though they will likely not find that out from the videos themselves, as those, sadly, demonstrate what’s possible for the future, not what’s available now. Researcher uses card trick to reveal unconscious knowledge But the videos aren’t about the guy on the couch, they’re about showing off what can be done with simple existing technology and some old fashioned film-making trickery. To make them, the team used the Playstation Move, a Steadicam an EyeToy camera and some guys dressed in white body suits, girls with fish poles and other extras to manipulate various other objects such as tentacles. At any rate, in the videos a guy sits on his couch and the room around him changes as 3D imagery is projected onto all the surfaces around him, including the guys in the white suits. In one scene, the guy is morphed into a rocket and flies over a cityscape. It’s all very impressive stuff, perhaps even more so when taking into account that no fancy post-editing was allowed to insert computer generated imagery, or to remove stuff, such as the strings that held dangling objects. Also impressive is the fact that it was all done using a Steadicam, which had not been done before. The fact that the camera recording the videos is able to move about adds to the three-dimensional effect; something movie-makers and those that make commercials for television are likely to want as soon as possible.After all is said and done though, the coolest part of the whole project for those not a part of it, is just watching the videos they’ve produced, free of charge. Explore furthercenter_img Citation: Sony hints at holodeck future with captivating videos (2011, December 5) retrieved 18 August 2019 from https://phys.org/news/2011-12-sony-hints-holodeck-future-captivating.html (PhysOrg.com) — You have to hand it to the imaginative people at Sony, or at least those they partnered with at Studio Output and the Marshmallow Laser Factory; together the three have produced three videos that are likely to evoke feelings of nostalgia, even as they stir yearnings for more. The three videos, commercials, essentially for Sony’s Playstation Video store, show what the future may soon hold even as they remind us of what our collective imagination can inspire, the awe-inspiring holodeck of Star Trek fame. In the videos, which all involved claim were made with just one take and no postproduction work, a person is seen sitting on a couch experiencing what many a science fiction fan would give up many a day’s pay to experience for themselves; a true holodeck. © 2011 PhysOrg.comlast_img read more

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VM researchers post rude awakening about virtualization security

first_img(Phys.org)—A virtual machine stealing information from another virtual machine running on the same piece of hardware? That’s not supposed to happen. Virtual machines run various tasks on a single computer rather than relying on a separate machine to run each one. The assumption is that one can’t eavesdrop or tamper with the other. But now a technique reported in a paper, “Cross-VM Side Channels and Their Use to Extract Private Keys,” by Yinqian Zhang of the University of North Carolina, Chapel Hill, and computer scientist colleagues from the University of North Carolina, University of Wisconsin, and RSA Laboratories, suggests a different story. © 2012 Phys.org This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: VM researchers post rude awakening about virtualization security (2012, November 9) retrieved 18 August 2019 from https://phys.org/news/2012-11-vm-rude-awakening-virtualization.html Explore further Researchers discover new way to patch holes in the ‘cloud’ More information: Research paper: www.cs.unc.edu/~reiter/papers/2012/CCS.pdf Diagram of the main steps in the side-channel attack. Credit: Yinqian Zhang et al. The researchers said they have completed the first demonstration of a successful side-channel attack on a virtualized, symmetric multiprocessing system, using a virtual machine manager (VMM). They said it is possible for one VM to steal the cryptographic keys that are in place to keep data secure from another running on the same physical hardware. This does not paint a happy blue-skies picture for computing facilities that leverage virtualization.In hours, they recovered the private key for a 4096-bit ElGamal-generated public key using the libgcrypt v.1.5.0 cryptographic library. They extracted the ElGamal decryption key stored on a VM running the GNU Privacy Guard. How it works: Both VMs share the same hardware cache, which stores data for use by the computer processor. The attacking VM fills the cache in a way that the target VM, which is processing a cryptographic key, may overwrite some of the attacker’s data. By looking at which parts of the cache are changed, the attacking VM learns about the key in use.”VM side channels” are likely to become familiar words to those who track security in cloud environments. The authors’ technique boiled down to “side-channel analysis,” in which a private key is cracked by studying the targeted cryptographic system’s behaviors. “In this paper,” said the authors, “we present the development and application of a cross-VM side-channel attack,” which they further described as an access-driven attack in which the attacker VM alternates execution with the victim VM and leverages processor caches to observe the behavior of the victim. The attack worked only when both attacker and target VMs were running on the same physical hardware or, in virtual computing language, as “co-residents” on a single machine. Co-author Ari Juels of RSA Laboratories said that one of the lessons to be learned is that virtualized machines running highly sensitive workloads should not be placed on the same hosts as potentially untrustworthy virtual machines.Ways to avoid such exploit headaches in the real world consist of countermeasures that administrators may take to avoid the leakage. One is to use a separate, “air-gapped” computer for high-security tasks.”In high-security environments, a longstanding practice is to simply not use the same computer to execute tasks that must be isolated from each other, i.e., to maintain an ‘air gap’ between the tasks. This remains the most high-assurance defense against side-channel (and many other) attacks,” the authors wrote.Other countermeasures may call upon side-channel resistant algorithms; the authors also mentioned “core scheduling.” The paper said, “Another defense might seek to modify scheduling to at least limit the granularity of interrupt-based side-channels.”last_img read more

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Bell Labs researchers build camera with no lens

center_img More information: Lensless Imaging by Compressive Sensing, arXiv:1305.7181 [cs.CV] arxiv.org/abs/1305.7181AbstractIn this paper, we propose a lensless compressive imaging architecture. The architecture consists of two components, an aperture assembly and a sensor. No lens is used. The aperture assembly consists of a two dimensional array of aperture elements. The transmittance of each aperture element is independently controllable. The sensor is a single detection element. A compressive sensing matrix is implemented by adjusting the transmittance of the individual aperture elements according to the values of the sensing matrix. The proposed architecture is simple and reliable because no lens is used. The architecture can be used for capturing images of visible and other spectra such as infrared, or millimeter waves, in surveillance applications for detecting anomalies or extracting features such as speed of moving objects. Multiple sensors may be used with a single aperture assembly to capture multi-view images simultaneously. A prototype was built by using a LCD panel and a photoelectric sensor for capturing images of visible spectrum.via Arxiv Blog Journal information: arXiv © 2013 Phys.org The proposed architecture consists of two components: an aperture assembly and sensor of a single detection element. Credit: arXiv:1305.7181 [cs.CV] The process works because the image is built from light reflected off an object as measured from a slightly different perspective. Comparing the same view as seen through many different aperture array patterns allows for building a complete picture without the need for a lens.The upside to such a camera is its low cost—the demo made by the team at Bell Labs was constructed from off-the-shelf parts. Also, adding more sensors allows for creating multiple images simultaneously (three sensors allows for building three dimensional images). The downside to the process is that it takes much longer to take a picture than a lens based camera, and it only works for capturing stills.last_img read more

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Valve engineer builds mouthmouse and butt controller from other gadgets w Video

first_img A look inside a burning rocket engine Citation: Valve engineer builds mouth-mouse and butt controller from other gadgets (w/ Video) (2013, December 6) retrieved 18 August 2019 from https://phys.org/news/2013-12-valve-mouth-mouse-butt-gadgets-video.html © 2013 Phys.org (Phys.org) —Valve engineer Ben Krasnow is clearly one of those guys that sees things differently than the rest of us. How many people would look at an optical trackball, for example, and think to themself, hey, maybe I could make that work with my tongue. But that’s just what he’s done, taken the guts from an optical trackball, add a cable, changed out the bulb and attached it all to an orthodontic type retainer which he puts in his mouth to use as a controller that can be run by his tongue. And that’s just one device—he’s also created another gadget that a person sits on to control some of the action on a computer screen. Explore further Krasnow works for Valve, a virtual reality company, so he’s not just fooling around for fun—he and presumably others at Valve are knocking around trying to find replacements for mice, trackballs and other gesture control devices that hopefully at some point, will blur the interface between human and machine. Take the posture-based game controller Krasnow has built. He made it by taking apart a digital scale and adding in an Xbox controller and a standard mouse. The end result is a flat device that he sits on. Twirling on it causes panning onscreen—leaning forward or backward results in speeding up moving forward or backwards onscreen. Both devices seem obvious—how is it we don’t have both already?Neither of his devices is ready for mass production and sale, and they never may be, but both show hints of what might be coming as he and other engineers like him set their minds to thinking very seriously outside of the metaphorical box. The tongue-mouse, as he calls it might not be of much use to most people who use Windows—it’s accuracy is not up to standards, but for a paraplegic it might mean the difference between dependency on others and a whole new kind of freedom. In a similar vein, the posture-based controller looks like the beginnings of something new—perhaps future warplane pilots will sit on something similar, or more likely, gamers sitting in 360 degree pods, swiveling on their seats to gain an immersive experience unlike anything available today. We don’t often get to see the results of tinkering by corporate engineers—not unless it winds up in a finished product—it’s nice when it does happen—helping us enjoy some of the wonder that they experience first-hand when sudden inspiration strikes. Posture-based game controller This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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BJPSena alliance finally breaks in Maharashtra

first_imgThe break-up came after days of bickering over which party will contest how many seats and who will be the chief ministerial candidate.”We tried out level best till the very last to save the alliance,” a grim looking Fadnavis told the media. “However, there was no suitable proposal from the Shiv Sena on the issue of seat-sharing which could honourably accommodate all the partners. “Hence we have decided to go our independent ways,” he said. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJIThough there was no immediate response from the Shiv Sena, the party is expected for now to continue in the BJP-led central government of Narendra Modi.Senior BJP and Shiv Sena leaders had indicated to IANS on Sep 19 that the alliance was virtually over.”It’s on the verge of breaking. Only a formal announcement is awaited,” a senior BJP leader had said.Similarly, a Shiv Sena functionary hinted to IANS that the alliance “is over” but the party had decided to wait for further developments before declaring its stand. Also Read – Health remains key challenge in India’s development: KovindThe leader of the opposition in the Maharashtra assembly, BJP’s Eknath Khadse, said the Shiv Sena’s discussions centred more on the post of chief minister.”Our united efforts were to rid Maharashtra of the Congress-NCP combine at any cost. Other things would follow,” Khadse said, reiterating the party’s stand.The Shiv Sena and the BJP were part of a six-party “Grand Alliance” that included four smaller parties. The alliance was widely expected to seize power in the upcoming assembly elections.last_img read more

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Books open up our minds Mamata

first_imgKolkata: Describing books as a person”s best friend, West Bengal Chief Minister Mamata Banerjee today urged people to cultivate a reading habit as it is good for the mind. “Today is World Book and Copyright Day. Books are a person’s best friend. They open up our minds. We must work together to preserve the reading habit,” Banerjee tweeted this morning.World Book Day or World Book and Copyright Day is an annual event to promote reading, publishing and copyright.It is organised by the United Nations Educational, Scientific and Cultural Organisation.last_img read more

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CarDekhocom bags 50 mn in 2nd round of fund infusion

first_imgCarDekho.com, the flagship portal of GirnarSoft, has raised $50 million (over Rs 300 crore) in the second round of fund infusion. The funding was led by Hillhouse Capital with participation from Tybourne Capital and Sequoia Capital, the company said in a statement. “Elara Capital acted as the exclusive financial advisor to the transaction. With this, the parent company Girnar Software is now valued at $300 million,” it added. GirnarSoft CEO and Co-Founder Amit Jain said company’s aim is to have a global footprint through its innovative products and services. “This is the largest quantum of fund raise in this segment in India so far. We see the second round of investment as an endorsement of our strategy and progress so far,” he added.last_img read more

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