New unifying theory of lasers advanced by ...( New Haven Conn. Researchers at Yale...)

New Haven, Conn. Researchers at Yale and the Institute of Quantum Electronics at ETH Zurich have formulated a theory that, allows scientists to better understand and predict the properties of both conventional and non-conventional lasers, according to a recent article in Science.

The lasers that most people are familiar with emit a narrow beam of light in a fixed direction that has a well-defined wavelength and a predictable power output like those in laser pointers, bar-code readers, surgical instruments and CD players, said senior author A. Douglas Stone, the Carl A. Morse Professor of Applied Physics at Yale.

In these conventional lasers, the light is trapped and amplified between parallel mirrors or interfaces and bounces back and forth along one dimension. Scientists can determine what the light output will be based on the leakiness of the mirrors, which is usually quite small.

But, a new breed of lasers diffusive random lasers (DRLs) made possible by modern nanofabrication capabilities, consist of a simple aggregate of nanoparticles and have no mirrors to trap light. These lasers were pioneered by Hui Cao, now a professor of applied physics at Yale, and have been proposed for applications in environmental lighting (laser paint), medical imaging and displays. Until now, there has been no simple way for scientists to predict the wavelengths and intensities of the light emitted by DRLs.

Although, superficially, conventional lasers and DRLs appear to operate very differently, experimental results indicated many basic similarities, and scientists have searched for a unifying description that would apply to all lasers.

The properties of a laser are determined by measuring the lasing modes, including the pattern of light intensity within the laser, an
'/>"/>