When a grating is recorded in a bacteriorhodopsin film by two linear parallel polarized beams together with an auxiliary violet light, the diffraction efficiency has a dependence on the polarization orientation of the violet light as well as its intensity. A method for calculating the diffraction efficiency of gratings in bacteriorhodopsin is proposed based on the two-state photochromic model, considering the saturation effect and the polarization status of all the involved lights. It is found that the polarization orientation of the violet light produces an approximate-cosine and an approximate-sine modulation on the steady-state diffraction efficiency separately at low and high intensities, respectively. The parallel polarized violet light can improve the steady-state diffraction efficiency to a larger degree than the perpendicularly polarized violet light when both are at their optimal intensities. The optimal intensity for the parallel polarized violet light is lower than that of the perpendicular polarized one. Thus, the improvement of the steady-state diffraction efficiency is less sensitive to the intensity of perpendicular polarized violet light than to that of parallel polarized violet light.
© 2008 Optical Society of America
Diffraction and Gratings
Original Manuscript: February 4, 2008
Manuscript Accepted: March 13, 2008
Published: May 12, 2008
Baoli Yao, Peng Gao, Junhe Han, Liju Chen, Yingli Wang, and Ming Lei, "Influence of polarization orientation of violet light on the diffraction efficiency of bacteriorhodopsin," J. Opt. Soc. Am. A 25, 1274-1278 (2008)