Enhancement of speed of digital operation in bacteriorhodopsin based photonic switch

Nonlinear absorption based photonic switching of probe laser beam transmissions at 640 and 410 nm, respectively, by the nanosecond pump pulses at 570 nm, in bacteriorhodopsin (bR) protein molecules, has been analyzed theoretically using rate equation approach. The speed of digital operation in bR-based photonic switch is shown to be enhanced from earlier reported kHz to MHz. Further, the switching response is shown to be improved by biasing the sample with an additional laser beam at 410 nm. The technique can directly be applied to other rhodopsin proteins with similar photocycle to perform fast switching. Analyses demonstrate the utility of slow photochromic materials, having some energy states with fast relaxation rate, to perform fast photonic switching.