Scientists build world's first anti-laser

People have thought of the concept of the anti-laser, but until now no one really fleshed out the idea. The anti-laser could be used in optical computing and radiology.
Written by Boonsri Dickinson, Contributing Editor

Scientists at Yale University dubbed it the world's first anti-laser. Normally lasers give off lots of light, but this laser system traps light waves until they are absorbed. This is the opposite of what a normal laser is supposed to do.

The scientists introduced the theory of the anti-laser last year. Now, they have a working prototype of the anti-laser to show off. It's called coherent perfect absorber (CPA).

Yale physicist Douglas Stone's eureka moment occurred when he was talking to another scientist about if it was possible to understand lasers by knowing how they worked in reverse. Stone was turned on by the prospect of building an anti-laser, where it would absorb the light instead of function like conventional lasers that emit light.

According to Yale, the researchers:

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.

The CPA absorbs 99.4 percent of the light, but it should be able to absorb 99.999 percent. Theoretically at least. In addition to absorbing visible light, the laser can handle specific infrared frequencies. If you're still wondering how the anti-laser works, check out a diagram that explains all things CPA.

The researchers anticipate the discovery could have applications in:

  • optical switches
  • detectors
  • parts for optical computers
  • radiology for treatment or imaging

This post was originally published on Smartplanet.com

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