菌紫质薄膜光致折射率变化的理论计算和实验测量

Theoretical Calculation and Experimental Measurement of Photoinduced Refractive Index Change of Bacteriorhodopsin Film

基因改性细菌视紫红质BR D96N由于M态寿命的延长而具有显著的光致变色特性 根据Kramers Kronig变换关系,样品吸收光谱的变化会引起样品折射率的变化 本文首先从实验上测量了BR D96N薄膜样品在光激发前后的吸收光谱,然后根据Kramers Kronig变换关系,理论计算了对应此光致变色光谱变化的光致折射率变化光谱 实验上为了直接测量样品的光致折射率变化,采用Michelson干涉方法测量BR D96N薄膜在不同探测波长下的光致折射率变化量。

BR-D96N is a genetic mutant of bacteriorhodopsin (BR) with obviously photochromic characteristic benefiting from the prolonged lifetime of the M state. According to the Kramers-Kronig relation the absorption spectrum change of a sample will cause the refractive index change. In this paper, the autors firstly measured the absorption spectra of the BR-D96N film before and after light irradiation. Then the refractive index change spectrum of the sample is calculated according to the Kramers-Kronig transformation. In order to directly measure the photoinduced refractive index change of the bacteriorhodopsin film, Michelson interferometer is used to measure the refractive index change at different wavelength. The experimentally measured values were compared with the theoretically calculated curve.