Laserati

"Plausible deniability" is an added benefit of laser weapons according to US Air Force Research Laboratory. via: NewScientist

Cynthia Kaiser, chief engineer of the US Air Force Research Laboratory's Directed Energy Directorate, used the phrase "plausible deniability" to describe the weapon's benefits in a briefing (powerpoint format) on laser weapons to the New Mexico Optics Industry Association in June.

John Corley, director of USAF's Capabilities Integration Directorate, used the same phrase to describe the weapon's benefits at an Air Armament Symposium in Florida in October 2007 (see page 15, pdf format).

As the term suggests, "plausible deniability" is used to describe situations where those responsible for an event could plausibly claim to have had no involvement in it.

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I found this presentation on Google Video: Active galactic nuclei with laser guide star adaptive optics. It is from the AAS 212th Meeting. The presenter is Claire Max.

Adaptive optics on the current generation of 8 - 10 meter telescopes yields spatial resolutions in the near-infrared comparable to those of Hubble at visible wavelengths. Laser guide stars are now making these high spatial resolutions available over a large fraction of the sky. I will describe several areas in which these advances are being applied to AGN science: 1) measurement of black hole masses in nearby galaxies from kinematics of stars and gas; 2) study of the spatial distribution of stellar populations and dust in galaxies at 0.5 < z < 1.5, and 3) tests of the relationship between galaxy mergers and AGN activity. I will conclude with a discussion of the planned Next Generation Adaptive Optics system at the W. M. Keck Observatory, outlining the expected improvements in AGN science with this new system.

The authors of the time lapse movie are Stéphane Guisard, Valère Leroy and Jean Pajus. It is fun to see the PARSEC laser pointing to different directions of the universe over the night. I wonder what the night sky would look like in Hawaii, where there are several guide star lasers.

This is a time lapse movie made from individual images taken with a Canon 20Da camera and a 8mm lens. This accelerated movie shows a complete night at Paranal Observatory starting at sunset and finishing at dawn. That night, the Laser Guide Star Facility was in use and its yellow sodium Laser beam left its footprint on our movie. The laser beam creates a Laser Guide Star in the high atmosphere, 90 km above us. This ‘bright’ artificial star helps the adaptive optics system located in the main telescope, to measure and correct the distorsions of the images produced by the atmosphere, in real time and several hundreds of times per second.

The bright part of the Milky Way, containing the galactic center, is disappearing to the west on the left hand side of the movie. The Andromeda galaxy is visible also, as a diffused and elongated spot crossing the sky just above the domes. One can also see the Pleiades and “upside down” Orion constellation rising (remember this movie is done from the Southern hemisphere) together with the other half of our Milky Way . Finally the moon lightens the morning sky just before sunrise.

An image-guided femtosecond laser is allowing surgeons to remove individual cancer cells while adjacent cells remain intact.

Researchers from the Universities of Texas and Stanford, US have demonstrated a miniaturized probe that enables ablation of single cells and subcellular structures at high precision. The tool combines two-photon microscopy and femtosecond laser microsurgery in a 10x15x40 mm housing (Optics Express 16 9996).

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Paolo Villoresi and his colleagues at the University of Padova in Italy, in collaboration with the group of Anton Zeilinger in Austria, have taken the first step to establishing quantum communications in space by exchanging single photons from an orbiting satellite to Earth.

They demonstrated how the Matera Laser Ranging Observatory in Matera, Italy, used for satellite laser ranging with ultimate precision, can be adapted as a quantum communication receiver to detect single quanta emitted by an orbiting source—in this case a Japanese low-Earth-orbiting satellite. They also identified the exact techniques needed to detect the very weak quantum signal to be exploited in a dedicated satellite.

The research will be presented at the 2008 Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS) May 4-9 at the San Jose McEnery Convention Center in San Jose, Calif.

Source: Optical Society of America

Image from CRIMSON.

There is an article on the Harvard Crimson, reporting and explaining how a special type of laser, namely Astro-Comb, can help in the search for other earth-like planets.

Physicists in the US and Australia have used the quantum nature of light to make an important step towards improving the sensitivity of kilometre-sized interferometers used to search for gravitational waves. By using light in a “squeezed state” they achieved a 44% improvement in sensitivity of a prototype gravitational-wave detector.

This figure could reach 300% in a full-scale detector and the team believes that squeezed-light sources could be tested in working detectors such as LIGO within 1-3 years. More sensitive detectors would be able to search larger volumes of the universe for sources of gravitational waves, making their detection more likely.

More at PhysicsWorld

A group of European researchers had triggered electrical activity in thunderstorms for the first time, using a terawatt femtosecond mobile laser. They did this by aiming their laser to thunderclouds. via: OSA

The intense laser pulses created plasma filaments in the atomosphere that could conduct electricity akin to Benjamin Franklin's silk kite string. No big lightning was triggered because the plasma filaments were still too short-lived.

"This was an important first step toward triggering lightning strikes with laser beams," says Jérôme Kasparian of the University of Lyon in France. "It was the first time we generated lighting precursors in a thundercloud." The next step of generating full-blown lightning strikes may come, he adds, after the team reprograms their lasers to use more sophisticated pulse sequences that will make longer-lived filaments to further conduct the lightning during storms.

Triggering lightning strikes is an important tool for basic and applied research because it enables researchers to study the mechanisms underlying lightning strikes. Moreover, triggered lightning strikes will allow engineers to evaluate and test the lightning-sensitivity of airplanes and critical infrastructure such as power lines.

The hottest buzz right now in technology blogosphere is that Mitsubishi unveils Laser TV at a Consumer Electronics Show 2008 in Las Vegas.

Photo from PopSci

It is not the first time a laser TV is unveiled. Be remindered that a Chinese company had unveiled a 120 inch laser TV last year. As for the advantage of laser TV, you can check this post and the wikipedia article.

Professor, US Navy team up to diagnose decompression sickness

It
may not rank among the top 10 causes of death, but decompression
sickness can be fatal. Instead of waiting for symptoms to appear, a
University of Houston professor is developing a laser-based system that
can diagnose the sickness in a matter of seconds.

Kirill Larin, assistant professor of biomedical engineering
and mechanical engineering, is using a $400,000 grant from the U.S.
Navy to develop the first optical non-invasive tool to test those most
likely to suffer from decompression sickness, such as scuba divers,
submariners and airplane pilots. Decompression sickness affects those
who experience sudden, drastic changes in the air or water pressure
surrounding their bodies. It can cause anything from joint pain – known
as the bends – to seizure, stroke, coma and, in the most extreme cases,
death.