Fast photonic switching in pharaonis phoborhodopsin protein molecules

Laser intensity induced nonlinear absorption based photonic switching in pharaonis phoborhodopsin (p pR) protein molecules has been analyzed theoretically, using a rate equation approach. The probe beam transmissions at 560 and 390 nm, respectively, have been shown to be switched by nanosecond pump pulse excitation at 498 nm. Fast digital operation with ∼250 ns switching time is achieved by utilizing its K -intermediate state population changes. The presently observed switching speed (∼250 ns) in p pR is much higher in comparison to earlier reported values in milliseconds and seconds in different rhodopsin protein molecules. Analysis provides the scheme for fast photonic switching with slow photochromic materials having some fast energy states. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)