Influence of auxiliary violet light on holographic diffraction efficiency under different recording intensities in bacteriorhodopsin film

Abstract

The photochromic bacteriorhodopsin (BR) film can be used as a rewritable holographic recording medium. Due to the scattering and the reflecting of light from the BR film, the grating contrast of the hologram is diminished during the hologram recording. When the intensity of the recording light is weak, the influence of the scattering and reflection on the grating contrast is low enough to be neglected. But in the case of intense recording light, this influence should not be overlooked. It is found that the influence of the auxiliary violet light on the holographic diffraction efficiency kinetics is distinct under different recording intensities. At weak recording light intensities, the steady diffraction efficiency are increased and the peak diffraction efficiency is suppressed by the auxiliary violet light. But for intense recording light, the steady diffraction efficiency as well as the peak diffraction efficiency are both increased by the auxiliary violet light. Based on the two-level model of BR photochromism, we give a good theoretical explanation to the above phenomena.