MODELING THE GRATING-FORMATION PROCESS IN THICK BACTERIORHODOPSIN FILMS

We model the grating-formation process in bacteriorhodopsin films for the interference of two plane waves. We simulate the temporal dependen ce of grating recording and readout, and we examine the behavior of th e diffraction efficiency with respect to exposure, write and read wave lengths, and film parameters such as initial optical density and lifet ime of the upper state. Gratings written in thick. bacteriorhodopsin f ilms are generally nonuniform and nonsinusoidal owing to the absorptio n and saturation properties of the material. The simulations also show that one can often obtain optimization of hologram recording and read out by writing and reading at wavelengths far off the peak of the grou ndstate absorbance spectrum, especially for films with high values of the peak optical density. (C) 1998 Optical Society of America.