U.S. researchers have announced the development of the world's first "anti-laser," which they call a coherent perfect absorber (CPA), 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 discovery could pave the way for a number of novel technologies with applications in everything from optical computing to radiology. The anti-laser device can focus two laser beams of a specific frequency into an optical cavity made from silicon, trapping the incoming beams of light and causing them to bounce around until all their energy is dissipated in the form of heat. Changing the wavelength of the incoming light switches the anti-laser on and off, creating an optical switch that could be the basis of a very fast optically-based computer.
Currently the CPA can absorb 99.4 percent of all light fed into it, but the research team responsible for building it believes they can increase that number to a near-perfect 99.999 percent.