In the anti-laser, incoming light waves are trapped in a cavity
where they bounce back and forth until they are eventually absorbed.
Their energy is dissipated as heat. (Photo: Yidong Chong)
Alright, so about fifty years ago we saw the first invention of what
we know today as the laser, and at that time nobody really knew what to
do with it. The technology was discovered, but it did not yet have any
practical application at that time. Well, it now seems to be happening
again. Technology discovered for which there may not yet be any concrete
application. Ironic then to think that this new technology we are
talking about is in fact an anti-laser. Yes, you read it correctly.
Anti-laser.
Scientists at Yale University have built the world’s very first
Anti-laser. Incoming beams of light interfere with one another in such a
way as to perfectly cancel each other out, and although there is no
definite plan for what to use the technology yet, the possible
applications seem to be varied and wide open when it comes to
considering the possibilities.
Some of the fields of use include optical computing to radiology.
Current day lasers produce a focused beam of coherent light-light
waves with the same frequency and amplitude that are in step with one
another.
Just one year ago, Yale physicist A. Douglas Stone and his team,
published their on theory on how an Anti-laser would work, and
demonstrated that it would indeed be possible to build such a device
using silicon. Now just one year later, the team has managed to build
the world’s first functioning Anti-laser. The team also calls the device
a coherent perfect absorber (CPA).
The results appear in the Journal of Science’s February 18 issue. The
team focussed 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.
It is believed that CPAs may one day be used as optical switches,
detectors and other types of components in next generation computers, or
optical computers. These will be powered by light as well as electrons.
Once the technology has been refined, it is believed that a CPA
should be able to absorb 99.999 percent of incoming light. The CPA we
built is just a proof of concept,” Stone said. “I’m confident we will
start to approach the theoretical limit as we build more sophisticated
CPAs.” Similarly, the team’s first CPA is about one centimeter across at
the moment, but Stone said that computer simulations have shown how to
build one as small as six microns (about one-twentieth the width of an
average human hair)