Wednesday, September 02, 2009

"WIRELESS: Nanoscale laser harnesses plasmons"

Semiconductor lasers could someday be used to shuttle light around chips instead of electrons, but not until they are shrunk to the nanoscale. Now researchers think they may have found the key--confining light in waveguides smaller than their own wavelength then linking them to electron waves called plasmons. Look for electronic chips with integrated optics within five years. R.C.J.

What is being billed as the world's smallest semiconductor laser boasts a 5-nm active region that is 20 times smaller than the wavelength of the light it emits. The key to scaling down the laser to the nanometer level was harnessing the interaction between light and surface plasmon waves. Last month, experimental laser collaborators at Cornell University, Norfolk State University and Purdue University performed an alternative nanoscale laser demonstration, but their device was not integrated onto a chip like the current device being demonstrated by the University of California at Berkeley. Discrete semiconductor lasers used in telecommunications equipment are measured in millimeters, but micron-sized semiconductor lasers are currently under development in many labs. The two lasers recently demonstrated are the first to reach the nanometer realm.