双波长激光作用下菌紫质薄膜的光学特性及应用研究

Bacteriorhodopsin (BR) is an excellent biomolecular material. However, it is the fact that the Bacteriorhodopsin has the M-state with lifetime in the magnitude range from milliseconds to seconds, which is neither suitable for permanent data storage nor suitable for ultrafast information processing. This NSCF proposal has the following objectives: 1. study the optical properties of bacteriorhodopsin film under two-wavelength excitation, such as enhancement of photoinduced anisotropy in Bacteriorhodopsin film by using two laser beams of different wavelengths with orthogonal polarization, ultrafast photoinduced anisotropy induced by the transition between the initial state B and the intermediate states K and I, as well as the permanent polarization of the state F. 2. reveal the basic mechanisms of laser interaction with BR molecular, providing the perspective for genetic engineering and chemical modification of BR molecular in both experiment and theory. The research proposal has the following contents: 1. Under two-wavelength excitation, test the flash-photolysis kinetic absorption spectra of the wild-type, genetic mutant and chemically modified BR films, light-induced absorption difference spectra, dichroism spectra, kinetic curves of photoinduced anisotropy, two-photon absorption cross section, nonlinear refractive index and etc. 2. Analyze the influence of the initial state of BR molecular (dark adaptation and light adaptation) and wavelength, polarization, as well as intensity of excitation beams on the optical properties of BR films. 3. In virtue of the new optical properties of the BR film under two-wavelength excitation, explore the new applications in image processing technology, ultrafast information processing, slow light and polarization encryption.

菌紫质薄膜是一种性能优良的生物分子材料，但现有的野生型、基因改良型和化学修饰型菌紫质分子的M态寿命大都在ms～s量级，这制约了其在超快信息处理和永久信息存储领域的应用。本项目旨在研究菌紫质薄膜在两束连续或脉冲激光作用下展现出的一些新奇光学特性，如两束波长不同的偏振光增强或抑制其光致各向异性、基于B态和K态或I态的超快光致各向异性、F态永久偏振等，探讨菌紫质分子与激光作用的微观机制，为菌紫质分子的改良和应用提供理论和实验依据。主要研究内容包括：测试不同初始状态的菌紫质薄膜在双波长偏振光作用下的吸收动力学曲线、差异吸收谱、光致各向异性动力学曲线、分子吸收截面和折射率等数据；分析分子的初始状态及两束激光的波长、偏振、光强等对菌紫质薄膜光学性质的影响规律；探索菌紫质薄膜在两束不同波长偏振光作用下的新光学特性在图像处理、超快信息处理、慢光和偏振加密等领域的新应用。

本项目围绕菌紫质的光学特性（如光致各向异性等）和菌紫质分子与激光相互作用的微观机制开展了深入的研究，还研究了基于这些光学特性的一些具体应用。项目执行期间,研究了菌紫质薄膜在偏振光作用下的吸收动力学特性、光致各向异性动力学特性和全息偏振光栅的衍射特性；还研究了在两束激光作用下，入射光的偏振和光强对菌紫质吸收特性、各向异性和所记录全息光栅衍射效率的影响。设计了一种基于菌紫质光致各向异性特性的相移器，并将该相移器应用于相移干涉计量；提出了一种新的两步相移干涉技术，并探索了该技术在相移干涉计量方面的应用。研究了不同纳米粒子参杂对光致聚合物全息存储材料缩皱性能和折射率调制度的影响。项目执行期间在Applied Optics、Journal of Modern Optics、Journal of Materials Science等SCI/EI期刊发表论文8篇。与中国科学院西安光学精密机械研究所开展了富有成效的合作研究，双方联名发表论文3篇。邀请在德国University Stuttgart的学者来校交流讲学。参与培养和指导博士生1名和硕士生6名(已毕业5名)。