中文摘要：

研究了弱光强下细菌视紫红质膜（bR膜）的自衍射特性，给出了弱光强下相干光在bR膜中产生的振幅光栅光强分布模型，并用ysin^a x近似表示透射光强分布，结果与实验吻合，给出了不同透射光强y与指数α的对应关系．结果表明，在bR膜及入射光波波长给定的情况下，入射光强越小，对应的α值越大，当入射光强为0．072／T（mW／cm^2）时，α等于1．计算出不同入射光强和入射角下的自衍射效率．结果发现，对应于最大衍射效率的最佳入射角为2°。

英文摘要：

The self-diffraction characteristics of bacteriorhodopsin （bR） film illuminated by weak light were studied. The model describing the distribution of the light intensity of the amplitude grating induced by interference light in bR film under weak light was given, and the distribution of the transmitted light intensity y from the amplitude grating was described approximately as ysinax, which was in agreement with the experiment. The relationship between y and a was obtained, which indicated that giveing the wavelength of incident light, the weaker the incident light intensity would become, the bigger a would get. When the incident light intensity was 0. 072/T （mW/cm^2）, a equaled to 1. From different incident intensities and incident angles, the self-diffraction efficiencies were calculated, from which it could be found that the optimal incident angle was 2° corresponding to the maximum diffraction efficiency.