New Haven, CT (SPX) Feb 24, 2011
More than 50 years after the invention of the laser, scientists at Yale University have built the world's first anti-laser, in which incoming beams of light interfere with one another in such a way as to perfectly cancel each other out.
The discovery could pave the way for a number of novel technologies with applications in everything from optical computing to radiology.
Conventional lasers, which were first invented in 1960, use a so-called "gain medium," usually a semiconductor like gallium arsenide, to produce a focused beam of coherent light-light waves with the same frequency and amplitude that are in step with one another.
Last summer, Yale physicist A. Douglas Stone and his team published a study explaining the theory behind an anti-laser, demonstrating that such a device could be built using silicon, the most common semiconductor material.
But it wasn't until now, after joining forces with the experimental group of his colleague Hui Cao, that the team actually built a functioning anti-laser, which they call a coherent perfect absorber (CPA).
The team, whose results appear in the Feb. 18 issue of the journal Science, focused two laser beams with a specific frequency into a cavity containing a silicon wafer that acted as a "loss medium."
The wafer aligned the light waves in such a way that they became perfectly trapped, bouncing back and forth indefinitely until they were eventually absorbed and transformed into heat.
Stone believes that CPAs could one day be used as optical switches, detectors and other components in the next generation of computers, called optical computers, which will be powered by light in addition to electrons.
Another application might be in radiology, where Stone said the principle of the CPA could be employed to target electromagnetic radiation to a small region within normally opaque human tissue, either for therapeutic or imaging purposes.
Theoretically, the CPA should be able to absorb 99.999 percent of the incoming light. Due to experimental limitations, the team's current CPA absorbs 99.4 percent.
"But the CPA we built is just a proof of concept," Stone said. "I'm confident we will start to approach the theoretical limit as we build more sophisticated CPAs."
Similarly, the team's first CPA is about one centimeter across at the moment, but Stone said that computer simulations have shown how to build one as small as six microns (about one-twentieth the width of an average human hair).
The team that built the CPA, led by Cao and another Yale physicist, Wenjie Wan, demonstrated the effect for near-infrared radiation, which is slightly "redder" than the eye can see and which is the frequency of light that the device naturally absorbs when ordinary silicon is used.
But the team expects that, with some tinkering of the cavity and loss medium in future versions, the CPA will be able to absorb visible light as well as the specific infrared frequencies used in fiber optic communications.
It was while explaining the complex physics behind lasers to a visiting professor that Stone first came up with the idea of an anti-laser.
When Stone suggested his colleague think about a laser working in reverse in order to help him understand how a conventional laser works, Stone began contemplating whether it was possible to actually build a laser that would work backwards, absorbing light at specific frequencies rather than emitting it.
"It went from being a useful thought experiment to having me wondering whether you could really do that," Stone said. "After some research, we found that several physicists had hinted at the concept in books and scientific papers, but no one had ever developed the idea."
Share This Article With Planet Earth
Learn about laser weapon technology at SpaceWar.com
Yale scientists build 'anti-laser'
New Haven, Conn. (UPI) Feb 17, 2011
U.S. researchers have announced the development of the world's first "anti-laser," a device that can absorb and cancel out a laser beam. Scientists at Yale University say the silicon-based device can absorb an incoming laser beam entirely, converting its light to heat energy, the BBC reported Thursday. The technology could lead to a new generation of supercomputers using light rather th ... read more
Israel successfully tests Arrow anti-missile system|
Knesset urges $1.4 billion Iron Dome buy
Surface Combat Systems Center Tests Aegis BMD Capabilities
Boeing And Northrop Grumman Submit Proposal For Missile Defense Competitive Contract
Russia vows to sell missiles to Syria
Enhancing The Protection Of Rotary Aircraft Against Missiles
JLENS Program Achieves Critical Milestone
System Integration Test For SM-3 Kinetic Warhead Completed
Fire Scout Completes First Unmanned Test Flights On Littoral Combat Ship
K-MAX Achieves Numerous Firsts During Recent Demo Flights
Northrop Grumman Awarded UAS Common Architecture Working Group Contract
AeroVironment Develops World's First Fully Operational Life-Size Hummingbird-Like Unmanned Aircraft for DARPA
Northrop Grumman Next-Gen FBCB2 System Approved For Fielding
Boeing To Demonstrate Aviation Command And Control Subsystem For US Marine Corps
RC-12X Aircraft Provides Highly-Capable SIGINT Systems To Warfighter
ThalesRaytheonSystems Announces Command View Mobile For C4I Solution
LockMart Receives Major Contract Modification For F-22 Raptor Sustainment
Boeing Receives Second Option Of B-52 Engineering Sustainment Contract
A Device Enables The Remote Explosion Of Improvised Land-Mines
Boeing EA-18G Growlers Deployed by US Navy
Despite turmoil, Mideast arms sales boom
Tanker victory spells risks for Boeing
China's Huawei seeks US government probe
EADS 'disappointed and perplexed' by US tanker decision
US top military officer visits Gulf amid Arab revolts
Taiwan cardinal eyes China-Vatican dialogue
Mideast unrest puts US military access in jeopardy
US: Troops' move depends on Japan
Scientists Build World's First Anti-Laser
Yale scientists build 'anti-laser'
'Air laser' could find bombs at a distance
ONR Achieves Milestone In Free Electron Laser Program
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement|