title: Controllable snail-paced light in biological bacteriorhodopsin thin film.
abstract: 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.
authors.affiliation: Physics Department, University of Massachusetts, Boston, Massachusetts 02125, USA. 5pengfei@gmail.com
authors.forename: Pengfei
authors.initials: P
authors.lastname: Wu
authors.forename: D V G L N
authors.initials: DV
authors.lastname: Rao
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000528:radiation effects*; D003198:Computer Simulation; D004307:Dose-Response Relationship, Radiation; D008027:Light; D008567:Membranes, Artificial; D008956:Models, Chemical; D010777:Photochemistry / Q000379:methods*; D011829:Radiation Dosage; D011874:Radiometry
chemical_list: D008567:Membranes, Artificial; D001436:Bacteriorhodopsins