MIRRORLESS ALL-OPTICAL BISTABILITY IN BACTERIORHODOPSIN

We report direct observations of all-optical mirrorless bistability as sociated with saturable absorption in three kinds of bacteriorhodopsin (BR) samples: wild-type BR in water solution and dispersed in thin fi lms of a polymer matrix as well as water solution of the genetically e ngineered mutant BR(D96N). The experiments are carried out with picose cond pulses at 532 nm. The values measured for the saturation intensit y are explained in terms of the relaxation of the excited M state popu lation to the B state of the BR photocycle for the three kinds of samp les studied.