Aug 26 2007
Frontiers in Optics 2007 (FiO), the 91st Annual Meeting of the Optical Society of America, will be held from Sept. 16-20 in San Jose, Calif., alongside Laser Science XXIII, the annual meeting of the American Physical Society Division of Laser Science.
Gigantic Photoresponse Can Speed Up Optical Switches for Faster Internet Speeds
New research shows that an ultrafast, ultralarge change in reflectivity can be brought about with femtolasers, those that deliver pulses just quadrillionths of a second in length. Dramatic reflectivity changes will be useful in bringing about direct ultrafast optical-to-optical switches for quicker Internet data transfer, faster computers and other applications. In a recent experiment, femtosecond laser pulses falling on an organic salt target momentarily changed the material from an insulator (a bad reflector of light) to a semi-metal (a good reflector of light). The change in reflectivity this large – more than 100% – has never been achieved before in a photonic material; photo-induced changes are usually more like a few percent. Researchers found that the laser pulse required doesn't even have to be particularly intense to cause the change.
This "gigantic photoresponse" work began as a Tokyo Institute of Technology - Kyoto University collaboration but now also includes the U.S.' Lawrence Berkeley Laboratory and the U.K.'s Oxford University. The new advance is that the change in reflectivity can be brought about in tens of femtoseconds rather than 150 femtoseconds. The new results will be reported at the meeting by Jiro Itatani, who has a joint appointment at Lawrence Berkeley Laboratory and the Japan Science and Technology Agency. (Paper FWA2, "Ultrafast Gigantic Photo-Response in Organic Salt (EDO-TTF)2PF6 Initiated by 20-fs Laser Pulses")