Devin Powell reports for Discovery News:
A new antilaser device absorbs laser beams so well that barely a scrap of energy escapes. But if its whimsical name conjures up Star Wars–style visions of laser armor, curb your enthusiasm.
“This is the worst laser shield you could ever invent,” says Douglas Stone, a physicist and member of the Yale team that describes the device in the Feb. 18 Science. Because the antilaser soaks up energy, “R2-D2 would melt into a puddle if protected by our device.”
Instead, the prototype antilaser — which absorbs only a narrow range of infrared wavelengths — may be useful for designing light-based devices integrated into electronic computer chips.
Other researchers have created similar devices, called coherent perfect absorbers, by repeatedly bouncing light between a mirror and a piece of absorbing material. What’s new, Stone says, is the discovery of the fundamental principle that makes these devices work: time reversal.
In the context of lasers, time reversal isn’t a way for scientists to travel back to childhood and fix their embarrassing mistakes. It’s a technique for rewinding and undoing a process by reversing the mathematics underlying it — in this case, by changing a plus sign to a minus sign to make the energy absorbed by the antilaser equal to the energy produced by a laser…
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