菌紫质光致变色吸收特性的二能级理论研究

采用二能级模型(B态和M态)简化菌紫质(bR)光循环过程,建立了菌紫质光致变色吸收特性的数学方程,数值计算了bR膜对570nm单光束和对570nm与412nm双光束的吸收特性.计算表明,bR膜的光吸收特性与入射光波长、入射光强、摩尔消光系数、光密度和M态寿命有很大的关系.bR膜用于光存储时,读出光强和M态寿命是影响bR读出使用时间的两个重要因素.570nm与412nm双光束作用于bR膜时,可以实现以光控光操作,但由于570nm黄光的透过动态范围要比412nm紫光的透过动态范围大得多,因而在实际应用中应以黄光作为信息光,紫光作为控制光.基于bR膜对黄、紫光束的吸收特性,可以将其应用于亮背景滤除、反象器、图象相减、光寻址空间光调制器等光信息处理领域.

THEORETICAL STUDIES OF PHOTOCHROMIC ABSORPTION PROPERTIES OF BACTERIORHODOPSIN WITH TWO-LEVEL MODEL

Based on two-level model (B state and M state) of bacteriorhodopsin (bR) photocycle, mathematical equations of the photochromic absorption properties of the bR film are formulated. The absorption properties of 570nm single beam as well as 570nm and 412nm double beams are numerically calculated. It is indicated that the optical absorption is greatly dependent on the wavelength, incident light intensity, molar extinction coefficient, optical density and the lifetime of M state. The readout light intensity and the lifetime of M state are two significant factors which in fluence the total readout time of the recorded bR film. Under double beams illumination at wavelength of 570nm and 4122nm the bR film can realize the operation of light controlled by light. However, as dynamic range of the 570nm beam’s transmission is much broader than that of the 412nm, practically the 570 nm beam is suitable for being signal light while the 412nm beam is suitable for being control light. On basis of the optical absorption properties the bR film can be used in many fields of optical information processing such as bright background filtering,image reversing,images subtracting, optically addressed spatial light modulator and so on.