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World's first anti-laser demonstrated

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February 20, 2011

In the anti-laser, incoming light waves are trapped in a cavity where they bounce back and...

In the anti-laser, incoming light waves are trapped in a cavity where they bounce back and forth until they are eventually absorbed (Image: Yidong Chong/Yale University)

Much to the distaste of James Bond villains everywhere, scientists from Yale University recently demonstrated not a new, more powerful type of laser, but actually its opposite – the world’s first anti-laser. The device receives incoming beams of light, which interfere with one another in such a way as to cancel each other out. It could apparently have valuable applications in a number of technologies, such as optical computing and radiology.

Lasers work by using a “gain medium,” often gallium arsenide or some other semiconductor, to produce light waves with the same frequency and amplitude. These waves, which are in step with one another, make up a focused beam of coherent light.

By contrast, the anti-laser utilizes a silicon wafer “loss medium.” When two laser beams were shone into a cavity containing that wafer, it aligned the light waves so that they became “perfectly trapped,” causing them to ricochet back and forth until they were absorbed and transformed into heat.

The anti-laser, officially known as a coherent perfect absorber (CPA), is about one centimeter across, and capable of absorbing 99.4 percent of incoming light. According to Yale physicist A. Douglas Stone, however, the current model is merely a proof-of-concept. He believes that future versions should be able to absorb 99.999 percent of the light, and could be built as small as six microns – approximately one-twentieth the width of a human hair. The current CPA is also limited to absorbing near-infrared light, but Stone believes that by altering the cavity and the loss medium, future versions should be able to handle visible and infrared light.

CPAs could reportedly find use in optical computers, serving as components such as optical switches or detectors. Stone believes they could also be used in radiology, where they could focus electromagnetic radiation to a small region within opaque human tissue, for imaging or therapeutic purposes.

The research was just published in the journal Science.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
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4 Comments

there is nothing as absorbing energy. It must transfer it into another type of energy, typicaly heat.

Tomáš Kapler
21st February, 2011 @ 01:23 am PST

Imagine if this tech could be applied to solar panels?

Terry Penrose
21st February, 2011 @ 04:14 pm PST

They said anti laser*, because they use near infrared. Near Infrared are at lowest band in EM and light below this range convert to radio wave(Far infrared) and heat in this case.

*Anti laser, theory base on idea of of consistent wavelength and both sources at same precise opposite angle, both cancel each other. Currently we can do with laser only

Anyway, congratulation! at least we learn that light wave could be canceling.

Solar radiation came in various band.

twt
23rd February, 2011 @ 04:23 am PST

Sort of a "black hole" affect, just for a tiny part of the spectrum?

Will, the tink
3rd March, 2011 @ 05:44 am PST
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