Sun, 06 Jul 2008 11:05:57 BST CiteULike: dchens Rao http://www.citeulike.org/user/dchen/author/Rao CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2754427 <i>Physical Review Letters, Vol. 95, No. 25. (2005)</i><br /><br />We observe that the group velocity of light is reduced to an extremely low value of 0.091 mm/s in a biological thin film of bacteriorhodopsin at room temperature. By exploiting unique features of a flexible photoisomerization process for coherent population oscillation, the velocity is all-optically controlled over an enormous span, from snail-paced to normal light speed, with no need of modifying the characteristics of the incident pulse. Because of the large quantum yield for the photoreaction in this biochemical system, the ultraslow light is observed even at low light levels of microwatts, indicating high energy efficiency. Controllable Snail-Paced Light in Biological Bacteriorhodopsin Thin Film Pengfei Wu Rao doi:10.1103/PhysRevLett.95.253601 Physical Review Letters, Vol. 95, No. 25. (2005) 2008-05-04T19:36:43-00:00 2005 Physical Review Letters 95 25 APS 2006 biology cool film focus material optical