细菌视紫红质膜的光吸收非线性特性研究

对细菌视紫红质（ＢＲ）膜的光学吸收非性进行了研究,分别测量了细菌视紫红质光照前后的光吸收谱,结果显示它的吸收发生了明显的变化。用Ｚ扫描法研究了它的光学非线性,理论计算的结果表明它具有较大的光学非线性系数,且测量它的透过率随光强变化的关系曲线和理论模拟发现它对６３２．８ｎｍ波和匠光具有饱和吸收特性。     

基于细菌视紫红质薄膜的空间光调制器实验研究

阐述了利用细菌视紫红质薄膜（BR薄膜）优良的非线性光学特性作为光寻址的空间光调制器的实验研究.BR有两个重要的光敏中间态（B态和M态），其吸收带（B态吸收峰为570nm，M态吸收峰为412nm）重叠区域较少，利用其正向（B→M）和逆向（M→B）光反应之间转化关系和B态与M态的差异吸收实现了相干光学图像到非相干光学图像的转换实验.采用经基因改性的细菌视紫红质薄膜（BRD96N）材料，使用670nm相干光作为写入光，530nm非相干光作为读出光，得到了分辨率约为200 lines/mm，对比度约为2.1∶1的 关键词： 光寻址空间光调制器 细菌视紫红质薄膜（BR薄膜） 非线性光学特性 相干光与非相干光图像相互转换     

细菌视紫红质能化态时表面电位的非线性光学机制

用荧光标记物1，8-ANS与细菌视紫红质结合，测得紫膜细菌视紫红质在能化态时的表面电位远大于非能化态时的对应值。在细菌视紫红质分子的激光四波混频实验中，应用激子表象理论，获得了紫膜能化态时的激子饱和密度和激子长度，说明在bR—ANS络合物中，细菌视紫红质中色氨酸残基对ANS的激发能量转移效率提高，能化态时表面电荷密度增加，从而使非辐射共振转移变为激子转移，也证明了紫膜能化态时表面电位的非线性光学机制。     

BRD96N光调制吸收增强现象的实验研究

通过光谱响应特性实验和记录／读出图像实验，研究了基因变异型细菌视紫红质（BR_D96N）分子膜对单色光的光调制特性.发现BR_D96N分子膜在550nm—600nm范围内对调制光有吸收增强的现象，且对此范围内不同波长的单色光其调制程度有差异.利用曲线拟和方法发现550nm—600nm吸收增强的变化过程分为快过程和慢过程，其对应的时间常数分别为30s和5min.利用强度调制器的吸收强度与图像灰度之间的关系，分析了560nm—600nm范围内出现图像反转的实验现象. 关键词： 细菌视紫红质D96N分子膜 光谱响应 吸收增强现象 图像反转现象     

基于菌紫质的光开关原型器件研究

本文分析和讨论了细菌视紫红质的饱和吸收特性及互补抑制特性,在此基础上进行了细菌视紫红质光开关的实验研究。研究证明了被激发到M态的细菌视紫红质分子对紫光有较大的吸收,而处于基态的分子则对黄光有较大吸收。随着入射黄光强度的增加,菌紫质对黄光的吸收呈饱和吸收特必,时菌紫质对紫光呈较大吸收,而较强的紫光照射将会使此饱和吸收阈值增加,使得菌紫质对黄光的吸收又增大,从而黄光和紫光表现出互补透射特性。利用紫光和黄光控制菌紫质分子在M态和基态上的分布,我们实现了对不同的波长光和选通或者关闭,即光开关模型。     

细菌视紫红质高分辨图象存储中吸收和散射现象的实验研究

本文利用细菌视紫红质变种材料BR_D96N的基态和M态实现了图象的高分辨存储.实验研究了该样品的吸收特性;在此基础上分析了散射光对BR膜图象质量的影响,并通过合理的控制激发光强和激发时间在BR膜样品上得到分辨率为800lp/mm的高分辨图象.     

细菌视紫红质膜快速光开关的实验研究

建立了“脉冲激光－连续探测光－连续擦除光”的实验系统。在532nm的调Q脉冲激发光和不同波长的连续探测光作用下，研究了细菌视紫红质（BR）膜的光循环过程中的快速响应特性及各中间态的快速光吸收特性。观察到了微秒量级的快速光开关现象，并分析了激发光脉冲作用结束时，各中间态上细菌视紫红质分子的分布。     

用细菌视紫红质膜实现多进制数字光学运算

细菌视紫红质(bR)膜对黄光和蓝光的透射具有互补调制特性，由解黄光、蓝光透射光强的速 率方程而得到黄光和蓝光的互补抑制透射特性的解析表达式和图示结果.提出了无进位和无退 位的多进制数字光计算的矩阵加、减运算模型，构造了新型光计算的基本处理模式和计算结 构，设计了多进制矩阵的加法和减法的最佳实验方案，并用bR膜实现了多进制数字光矩阵的 减法运算实验操作. 关键词： 细菌视紫红质膜 数字光计算 运算结构 光调制     

信息光学 光计算

TP381 2005042805 用细菌视紫红质膜实现多进制数字光学运算=Digital op- tical operation in multilateral system by bacteriorhodopsin film[刊,中]／顾立群(南开大学物理学院．天津(300071)), 陈桂英…／／物理学报,-2004,53(12),-4236-4242 细菌视紫红质(bR)膜对黄光和蓝光的透射具有互补调制特性．由解黄光、蓝光透射光强的速率方程而得到黄光和蓝光的互补抑制透射特性的解析表达式和图示结果。     

Z-扫描技术与非线性光学材料性质的测量

介绍了Z-扫描技术的基本原理，以及Z-扫描技术在测量非线性光学介质的非线性折射率、非线性吸收系数和光学限制器等方面的应用，以细菌视紫红质(bR膜)、碘的酒精溶液和偶氮材料CN2为例，分别介绍了它们的测量结果，给出了提高Z-扫描灵敏度的改进方法，介绍了其发展装状况。     

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.     

Holographic simultaneous readout polarization multiplexing based on photoinduced anisotropy in bacteriorhodopsin

Bacteriorhodopsin (bR) is a reversible photochromic protein that can be used as a holographic medium. The dichroic absorption of the bR molecule is polarization dependent, thereby allowing for the recording of polarization holograms. The properties of polarization holograms can be used to multiplex two independent images in a single bR film. A new technique and associated polarization-multiplexing scheme are demonstrated that allow for simultaneous readout of two orthogonally polarized images while achieving a high normalized diffraction efficiency for each of the individual images.     

An all-optical time-delay relay based on a bacteriorhodopsin film

Using a special property of dynamic complementary-suppression-modulated transmission （DCSMT） in the bacteriorhodopsin （bR） film, we have demonstrated an all-optical time-delay relay. To extend our work, the relationship between the delay time of the all-optical time-delay relay and parameters of a bR film is numerically studied. We show how the delay time changes with the product of concentration and thickness （PCT） of a bR film. Furthermore, the shortest and longest delay times are given for the relay of ＇switch off. The saturable delay time and maximum delaytime of ＇switch on＇ are also given. How the wavelengths （632.8, 568, 533 and 412 nm） and intensities of the illuminating light influence the delay time is also discussed. The simulation results are useful for optimizing the design of all-optical time-delay relays.     

All-optical logic gates with bacteriorhodopsin

All-optical logic gates with bacteriorhodopsin (bR) protein molecules have been demonstrated based on all-optical switching of a cw probe laser beam by multiple pulsed pump laser beams due to nonlinear intensity-induced excited-state absorption. A cw probe laser beam at 640 nm corresponding to the peak absorption of O-state in the bR photocycle is switched by a pulsed pump laser beam at 570 nm corresponding to the maximum initial B state absorption, at relatively low powers. The switching characteristics have been used to design all-optical NOT and the universal NOR and NAND logic gates and the effect of various parameters such as variation in pump pulse width, pump intensity, lifetime of O state and absorption cross-section of the B state at probe wavelength on the switching characteristics has been analyzed.     

Analysis of low power spatial light modulation characteristics of bacteriorhodopsin

We present a detailed and accurate analysis of low power spatial light modulation characteristics of bacteriorhodopsin (bR) based on nonlinear intensity induced absorption. Amplitude modulation of probe laser read beam transmissions at 410 nm and 640 nm, corresponding to the peak absorption of M^II and O states of D96N bR and WT bR respectively, by the modulation laser write beam intensity-induced population changes at 570 nm has been analyzed, considering all intermediate states with both forward and backward transitions in the respective bR photocycles, using the rate equation approach. The SLM characteristics are shown to be sensitive to the normalized small signal absorption coefficient β, rate constants of M^II and O intermediate states and the absorption cross-section of the initial B state at the probe wavelength (σ_Bp). There exists an optimum value of β for which maximum percentage modulation can be achieved. It is shown that for extended M^II state lifetime of 250 s in D96N bR and O state lifetime of 2.2 s in WT bR, with σ_Bp= 0, 100% modulation of read beam transmissions can be achieved, leading to high dynamic range and sensitivity for low laser write beam intensities of 50 μW/cm² and 4 mW/cm² at 570 nm, respectively.     

细菌视紫红质的动态透射特性及其应用

细菌视紫红质 (Bacteriorhodopsin,简称 b R)是由嗜盐菌中提取出的一种光敏蛋白质 ,它是一种新型的生物光子学材料。我们测量的 b R膜在黄光和蓝光束分别照射下的非线性透射特性表明 ,在光照开始阶段 ,光的透过率随时间延长而增加 ,然后逐渐达到一个稳定值。黄光和蓝光的透过特性的不同是蓝光达到最大透过率的时间比黄光短。 b R膜在黄光和蓝光双光束同时照射下的非线性透射特性的计算结果表明 ,在某一固定蓝光光强 ,蓝光的透过光强随黄光强度的增加而减小 ,甚至变为零。这说明黄光对蓝光有抑制作用 ,即黄光可以调控蓝光的透过率。这一奇异的透射特性可以用做新出现事物滤波器     

Nonlinear Absorption Properties of nc-Si:H Thin Films

It is reported in this paper that the phenomenon of the saturated absorption of the exciton in hydrogenated nanocrystalline silicon (nc-Si:H) thin film fabricated by plasma enhanced chemical vapor deposition (PECVD) without any post-processing is observed at room temperature using pump-probe technology. This nonlinear optical absorption property is induced by the surface effect of the silicon nanoparticles in nc-Si:H thin films.     

Nonlinear optical study of palladium Schiff base complex using femtosecond differential optical Kerr gate and Z-scan techniques

A femtosecond differential optical Kerr gate (DOKG) and Z-scan techniques, have been applied to investigate the third-order optical nonlinearity of composite film of the coordination complex [PdLPPh₃] (L=N-(2-pyridyl)-N′-(salicylidene)hydrazine, PPh₃=triphenylphosphine). Film exhibits superior nonlinear optical properties in the near-infrared spectral region. The nonlinear response time and third-order nonlinear optical susceptibility of complex were found to be≤90 fs and 3.9×10^?10 esu, respectively. The Z-scan result shows that saturable absorption property of the film and its nonlinear absorption coefficient of the sample was found to be ?23 cm/GW.     

Low-power bacteriorhodopsin-silicon n-channel metal-oxide field-effect transistor photoreceiver

A bacteriorhodopsin (bR)-silicon n-channel metal-oxide field-effect transistor (NMOSFET) monolithically integrated photoreceiver is demonstrated. The bR film is selectively formed on an external gate electrode of the transistor by electrophoretic deposition. A modified biasing circuit is incorporated, which helps to match the resistance of the bR film to the input impedance of the NMOSFET and to shift the operating point of the transistor to coincide with the maximum gain. The photoreceiver exhibits a responsivity of 4.7 mA/W.