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LeopoldS

Ultrashort laser pulses squeezed out of graphene : Nature News & Comment - 1 views

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    isabelle: an option for space baed laser?
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    The fact that the graphene can emit laser pulses at different wavelengths might be interesting for spectroscopy and laser communications. The tiny dimensions might also help in miniaturization of devices (although apparently a conventional laser is necessary for pumping...). Maybe it would be possible to make very efficient displays with such a technology..?
Isabelle Dicaire

Testing of a femtosecond pulse laser in outer space : Scientific Reports : Nature Publi... - 2 views

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    Good news for fundamental physics and Earth system science, femtosecond lasers are now about to achieve space qualification thanks to fibre optics!  Applications include high resolution spectroscopy, absolute laser ranging, mapping of the geo-potential and testing of the theory of general relativity to name a few!
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    nice paper by the Koreans, did not know that they had already such a laser in orbit for a year. How much would this type be upscalable for our needs? in case we have not, we should reference it
jcunha

New laser to shine light on remote sensing - 3 views

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    A revolutionary new type of laser (fiber laser) is promising major advances in remote sensing of greenhouse gases.The new laser can operate (bed tuned) over a large range within the infrared light spectrum.
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    Reads too good to be true .... where is Isabelle when we need her ? :-)
jcunha

Laser filamentation in open air with mid-IR lasers - 0 views

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    First experimental study of laser filamentation in the mid-IR.
Thijs Versloot

Long-range chemical sensors using new high power continuum lasers - 0 views

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    Short range chemical analysis methods exist already, but using new high power lasers one could extend the operation length to e.g aircraft.
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    Isabelle?
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    The optical setup is very simple and lightweight: a compact semi-conductor DFB laser source and an all optical fiber system for amplification and supercontinuum generation. Interesting for space applications!
jcunha

A practical polariton laser - Nature Photonics - 2 views

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    One overview about a recent publication (10/06/2014 http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.236802) showing room temperature operation of a new type of laser 'discovered' in 2013, the polariton laser. This new type of laser shows extremely low threshold current density - 2 orders of magnitude below Vertical Cavity Surface Emitting Lasers (VCSEL) - and it is believed to become one important component of nanophotonic integrated components.
jcunha

First 'water-wave' laser created - 0 views

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    Technion researchers have demonstrated, for the first time, that laser emissions can be created through the interaction of light and water waves, in practice mechanical oscillations in fluids at the nanoscale. Interesting concept on the verge of two so far different fields!
Thijs Versloot

Laser #fusion passes milestone #NIF - 1 views

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    Machine breakeven reached at NIF, meaning 10kJ pushed into the pellet and a total output of17kJ. This is however a machine breakeven as it took several orders of magnitude more power to pump and fire 192 ns-lasers to achieve the input, but a tremendous achievement nonetheless after 60 years of fusion research
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    and I think the actual paper might be this one: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13008.html
Thijs Versloot

Record #Laser data transmission to the #moon achieved 622Mbps - 1 views

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    Oct. 22, 2013 NASA Laser Communication System Sets Record with Data Transmissions to and from Moon NASA's Lunar Laser Communication Demonstration (LLCD) has made history using a pulsed laser beam to transmit data over the 239,000 miles between the moon and Earth at a record-breaking download rate of 622 megabits per second (Mbps).
jcunha

Portable ultra-broadband lasers could be key to next-generation sensors - 0 views

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    Quantum Cascade Lasers are rising in the mid-infrared region, the so-called fingerprint zone of the electromagnetic spectrum for a whole bunch of chemical species that we are most of times interested in sensing. One more sign of the underlying importance of this technology comes just by seeing NSF, USHS, Naval Air Command and NASA as the main monetary contributors to this research.
santecarloni

Single-cell biological lasers : Nature Photonics : Nature Publishing Group - 0 views

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    Here, we show that fluorescent proteins4, 5 in cells are a viable gain medium for optical amplification, and report the first successful realization of biological cell lasers based on green fluorescent protein (GFP).
jmlloren

Experimental verification of the feasibility of a quantum channel between space and Earth - 0 views

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    Extending quantum communication to space environments would enable us to perform fundamental experiments on quantum physics as well as applications of quantum information at planetary and interplanetary scales. Here, we report on the first experimental study of the conditions for the implementation of the single-photon exchange between a satellite and an Earth-based station. We built an experiment that mimics a single photon source on a satellite, exploiting the telescope at the Matera Laser Ranging Observatory of the Italian Space Agency to detect the transmitted photons. Weak laser pulses, emitted by the ground-based station, are directed toward a satellite equipped with cube-corner retroreflectors. These reflect a small portion of the pulse, with an average of less-than-one photon per pulse directed to our receiver, as required for faint-pulse quantum communication. We were able to detect returns from satellite Ajisai, a low-Earth orbit geodetic satellite, whose orbit has a perigee height of 1485 km.
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    hello Jose! Interesting it was proposed to do the same with the ISS as part of the ACES experiment. I don't remember the paper but i can look if you're interested
Thijs Versloot

Lasers May Solve the Black Hole Information Paradox - 0 views

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    "In an effort to help solve the black hole information paradox that has immersed theoretical physics in an ocean of soul searching for the past two years, two researchers have thrown their hats into the ring with a novel solution: Lasers. Technically, we're not talking about the little flashy devices you use to keep your cat entertained, we're talking about the underlying physics that produces laser light and applying it to information that falls into a black hole. According to the researchers, who published a paper earlier this month to the journal Classical and Quantum Gravity (abstract), the secret to sidestepping the black hole information paradox (and, by extension, the 'firewall' hypothesis that was recently argued against by Stephen Hawking) lies in stimulated emission of radiation (the underlying physics that generates laser light) at the event horizon that is distinct from Hawking radiation, but preserves information as matter falls into a black hole."
annaheffernan

Filamentous laser beams point to new type of phase transition - applications in weather... - 2 views

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    Filaments of plasma created by a high-powered laser beam undergo a similar type of phase transition as liquid percolating through a porous material - that is the conclusion of physicists in Switzerland. The also describe the application of laser filamentation for directed lightening and encouraged rainfall - Isabelle should come back to take a closer look :p
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    Christophe? Isabelle?
jaihobah

The Nanodevice Aiming to Replace the Field Effect Transistor - 2 views

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    very nice! "For a start, the wires operate well as switches that by some measures compare well to field effect transistors. For example they allow a million times more current to flow when they are on compared with off when operating at a voltage of about 1.5 V. "[A light effect transistor] can replicate the basic switching function of the modern field effect transistor with competitive (and potentially improved) characteristics," say Marmon and co. But they wires also have entirely new capabilities. The device works as an optical amplifier and can also perform basic logic operations by using two or more laser beams rather than one. That's something a single field effect transistor cannot do."
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    The good thing about using CdSe NW (used here) is that they show a photon-to-current efficiency window around the visible wavelengths, therefore any visible light can in principle be used in this application to switch the transistor on/off. I don't agree with the moto "Nanowires are also simpler than field effect transistors and so they're potentially cheaper and easier to make." Yes, they are simple, yet for applications, fabricating devices with them consistently is very challenging (being the research effort not cheap at all..) and asks for improvements and breakthroughs in the fabrication process.
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    any idea how the shine the light selectively to such small surfaces?
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    "Illumination sources consisted of halogen light, 532.016, 441.6, and 325 nm lasers ported through a Horiba LabRAM HR800 confocal Raman system with an internal 632.8 nm laser. Due to limited probe spacing for electrical measurements, all illumination sources were focused through a 50x long working distance (LWD) objective lens (N.A. = 0.50), except 325 nm, which went through a 10x MPLAN objective lens (N.A. = 0.25)." Laser spot size calculated from optical diffraction formula 1.22*lambda/NA
LeopoldS

CubeSat to Demonstrate Miniature Laser Communications in Orbit | NASA - 0 views

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    laser link on cubesat!
jaihobah

Topological insulator laser - 2 views

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    These are lasers whose lasing mode exhibits topologically-protected transport without magnetic fields. The underlying topological properties lead to a highly efficient laser, robust to defects and disorder, with single mode lasing even at very high gain values.
Luzi Bergamin

[1107.0167] Nonlinear transformation optics and engineering of the Kerr effect - 9 views

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    The best paper on transformation optics written ever :-)
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    Finally something worth to read in the MM field!. The idea is excellent, congratullations. However, I think there is a typo or mistake in the definition of l=3x10-13 m, the "waist" of the laser beam. Seems clear that 0.3 pm is too small for being a waist of any laser beam.
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    Thanks for your commendation. Of course, the problem with nonlinear transformation optics is the same as with linear: it's very easy to come up with theoretical descriptions of devices that have the most absurd properties, but it will be extremely hard to fabricate them. But if you have any good suggestion, please shoot! About the laser beam: Pekka made the simulations, since I am not a "Comsolist", but still I think the numbers are correct. You are right that we should not call this a laser beam. Our problem was the following: we need to have a very simple model that can be simulated exactly (full Maxwell equations) but naturally exhibits self focusing. The Gaussian beam was the simplest solution. Since our model is purely classical and moreover we do not take into account diffraction effects, the parameter "l" is of minor importance. Taking "l" much larger gives almost the same picture but requires much more computer power to simulate. I guess that's why Pekka chose an unnaturally small number.
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    Concerning the fabrication... as usual, no idea. I agree that this is the main drawback of MM, and certainly difficult to overcome. I would double check that number, because its value is related with the beam shape of Fig. 1 A. I believe that the simulations are correct, it's just a detail.
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    wow ... still publishing despite babysitting and new job!!
santecarloni

Light bends itself round corners - physicsworld.com - 1 views

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    The Florida team generated a specially shaped laser beam that could self-accelerate, or bend, sideways.
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    very nice!!! read this e.g. "In addition to this self-bending, the beam's intensity pattern also has a couple of other intriguing characteristics. One is that it is non-diffracting, which means that the width of each intensity region does not appreciably increase as the beam travels forwards. This is unlike a normal beam - even a tightly collimated laser beam - which spreads as it propagates. The other unusual property is that of self-healing. This means that if part of the beam is blocked by opaque objects, then any disruptions to the beam's intensity pattern could gradually recover as the beam travels forward."
Thijs Versloot

Physicists create tabletop antimatter 'gun' - 0 views

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    Small scale laser induced electron accelerator followed by induced beta decay to produce positrons. Relatively simple, yet requires a high power fs laser and some precision engineering
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