辅助紫光提高菌紫质全息衍射效率的实验和理论研究

Experimental and theoretical studies on auxiliary violet light increasing the diffraction efficiency of holographic gratings in bacteriorhodopsin film

由于菌紫质样品的饱和吸收特性,在全息记录中,当记录光强大于样品的饱和光强时,全息光栅透过率随记录光相位差的分布远离余弦型,因此衍射效率的稳定值很低.菌紫质样品在红光和紫光共同作用下存在着双光束互补抑制效应,紫光可以抑制红光的透过率,提高红光的饱和光强,使记录区域由非线性区移至线性区,从而使全息光栅透过率随记录光相位差的分布变为余弦型,可以有效地提高全息衍射效率.实验证明,辅助紫光大大提高了菌紫质样品全息衍射效率的稳定值.根据此原理,建立了三光束全息光存储系统,在红光记录全息图的同时加入辅助紫光,可以使全息图衍射效率及衍射像的像质得到提高.

Due to the saturation absorption characteristic of bacteriorhodopsin film, in holography, when the intensity of the recording light is higher than the saturation intensity, the distribution of the transmission of the holographic gratings deviates from the cosine shape. As a result, the steady level of diffraction efficiency is very low. Using the mutual suppression property of bacteriorhodopsin films between the violet light and the red light, the saturation intensity of the film at 633nm can be increased by adding an auxiliary irradiation of 405nm violet light, which results in the holographic recording being changed from the nonlinear region to linear region. Consequently the distribution of the transmission of the holographic gratings retrieves to the cosine shape, and the diffraction efficiency is improved to a high value. Base on this principle, a three-beam holography system is set up. The diffraction efficiency and the quality of the diffraction image are shown to be greatly improved by the auxiliary violet light.