Making Light of Silicon; August 2005; Scientific American Magazine; by Steven Ashley; 1 Page(s)
Scientists have long sought to build lasers from silicon. Such an advance would enable engineers to incorporate both electronic and optical devices onto cheap silicon chips rather than being compelled to employ costly-to-make lasers based on "exotic" semiconductor materials such as gallium arsenide or indium phosphide. Silicon lasers could lead to affordable light-based systems that harness photons instead of electrons to shuttle huge amounts of data swiftly--at multigigabit-per-second rates. Two research groups, one at the University of California at Los Angeles and the other at Intel Corporation, have recently reported success in making silicon emit continuous laser light.
This much anticipated feat came despite silicon's dogged resistance to serving as a lasing medium. In a good lasing material, electrons that are pumped up with energy release that energy in the form of coherent photons of light. In silicon, however, excited electrons are more likely to vibrate, thus generating heat instead. "There have been many attempts, but no one had been able to get silicon to lase before now," notes Bahram Jalali, the physicist who led the U.C.L.A. team.