A researcher from the University of Nottingham and his Ukrainian colleague have built the world's first Saser: a device that generates a highly concentrated beam of sound waves at terahertz frequency. Not unlike the frenetic warblings of Welsh chanteuse Bonnie Tyler, when alternating layers of aluminum arsenide and gallium arsenide are exposed to an intense beam of light, photons are released, causing them to bounce back and forth between the layers. Eventually the sound waves combine into much stronger, highly concentrated sounds in which every particle is synchronized -- creating an ultra-high frequency "phonon" beam. Although practical applications for this technology have yet to be developed, it is hoped that Sasers could someday be used to probe an
