A laser is a device that emits a focused beam of light using a process of optical amplification. The beam produced is an assemblage of light waves joined together for a common purpose, such as performing delicate operations or pissing off low-flying pilots.
So an anti-laser instead of bringing light together for a common purpose, brings two sources of light together in such a way that they cancel each other out.
Yale physicist A. Douglas Stone published a study last year involving a proposed anti-laser that would function using common semiconductor component silicon. Now, with the help of colleague Hui Cao and his experimental team, the anti-laser is a reality.
They call the device a coherent perfect absorber, or CPA, which isn’t nearly as cool as anti-laser but will do in a pinch. Inside the CPA two beams of light at a specific frequency come together, using a wafer of silicon as a loss medium. The light is aligned in such a way that the two beams become trapped inside, bouncing around until absorbed, transformed into heat.
What good is an anti-laser? Stone believes the CPA could have applications in the field of optical computing. Next generation computers that run on a combination of light and energy could use these anti-lasers as components. Switches could be activated by the clashing of light inside microscopic CPA’s, for instance.
The current CPA is a bit large for such applications at 1cm across, but Stone says computer calculations show that one could be built as small as six microns, about the length of a human hair.
The most interesting fact about the anti-laser, may be how the idea came about. While explaining the physics behind how lasers work to a colleague, Stone suggested they think about how they work in reverse in order to better understand.
“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