Scientists build 'world's first' anti laser
1 min read
More than 50 years after the invention of the laser, scientists at Yale University have built what they claim to be the world's first anti laser, in which incoming beams of light are absorbed instead of emitted. According to the researchers, the discovery could offer significant advances in applications ranging from optical computing to radiology.
The team, whose results appear in the 18 February 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 then 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.
Yale physicist A Douglas Stone believes the anti laser, also known as a coherent perfect absorber (cpa), could one day be used as optical switches, detectors and other components in next generation optical computers, which use light and electrons for power. "The technology also has potential in radiology, where 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," he said.
According to Stone, the device should be able to absorb 99.999% of incoming light, but due to experimental limitations, it currently only absorbs 99.4%. "The cpa we built is just a proof of concept," he said. "But I'm confident that with some tinkering of the cavity and loss medium in future versions, it will be able to absorb visible light as well as the specific infrared frequencies used in fibre optic communications."
