Experimental study on polarization holographic storage in genetic mutant BR-D96N film

Recording with both parallel and orthogonal linearly polarized lights, polarization holographic storage in genetic mutant BR-D96N film is reported with both transmission type geometry and reflection type geometry. Polarization properties of diffraction light and scattering light are discussed for two different cases, parallel polarization recording and orthogonal polarization recording. It shows that, compared with recording with parallel polarization lights, orthogonal polarization holography can separate the diffraction light from the scattering noise, therefore improving the signal-to-noise ratio. It also shows that, compared with reconstruction with reference light, reconstruction with phase conjugated wave of the reference light can improve the signal-to-noise ratio of the reconstructed diffraction image, and also the wave-front aberration of the object light introduced by irregular phase object in the optical pass-way can also be corrected effectively, which ensures that the reconstructed diffraction image has a better fidelity. The preliminary angle-multiplexed volume holographic storage multiplexed by transmission type geometry and reflection type geometry is demonstrated in the BR-D96N film. Experiment shows that there is no cross-talk between the two pages of images except for some scattering noises.

Kinetic characterization of photoinduced anisotropy in diarylethene film

Based on the theoretical model we have proposed, a complete study on the kinetics of photoincluced anisotropy in diarylethene films is performed. The kinetic curves of molecular concentration, photoincluced dichroism and birefringence are calculated, respectively. It is found that the colored molecular concentration decreases with the increase of the excitation exposure until saturation, and the photoincluced anisotropy increases to a maximum and then decreases gradually. The optimal exposure is 260 J/cm(2). In addition, the transmittance of probe beam reflecting the anisotropy is measured by experiment. The theoretical results are compared with experimental data, and basic concordance is found between both sets of data. (C) 2008 Elsevier B.V. All rights reserved.

Kinetics of photoinduced anisotropy in bacteriorhodopsin film under two pumping beams

Photoinduced anisotropy in bacteriorhodopsin (BR) film arises from the selective bleaching of BR molecules to linearly polarized light. The kinetics of photoinduced anisotropy excited by single and two pumping beams are investigated theoretically and experimentally. Compared with a single pumping beam (650 nm), which produces comparatively small photoinduced anisotropy, dual-wavelength linearly polarized pumping beams (650 and 405 nm) can obviously change the photoinduced anisotropy. When the polarization orientation of the 405 ran pumping beam is perpendicular to that of the 650 nm pumping beam, the peak and steady values of the photoinduced anisotropy kinetic curves are remarkably enhanced. But when the two pumping beams have parallel polarization orientation, the peak and steady values are restrained. At a fixed intensity of the 650 nm pumping beam, there exists an optimal intensity for the 405 nm pumping beam to maximize the value of the photoinduced anisotropy. The photoinduced transmittance of the polarizer-BR-analyzer system is modulated by the polarization angle of the 405 nm pumping beam in an approximate-cosine form. (C) 2008 Optical Society of America.

Application of bacteriorhodopsin film for polarization phase-shifting interferometry

Photoinduced anisotropy in bacteriorhodopsin (BR) film is based on photoanisotropic selective bleaching of BR molecules under linearly polarized excitation light. It is modulated by the polarization orientation of the linearly polarized light. The anisotropic information recorded in the BR film is read by a circularly polarized light, which is in turn converted into an elliptical polarized light by the BR film. The rotation angle and the ellipticity of the elliptical polarized light are dependent on the polarization orientation of the linearly polarized excitation light. A phase-shifting interferometer based on the photoinduced anisotropy of BR film is presented theoretically and experimentally. Phase shift is controlled by the polarization orientation of the external excitation light, thus, the phase shift can be controlled without moving parts inside the interferometer, which contributes to the mechanical stability of the system.

遥爪丁腈共聚物的增韧环氧－聚氨酯IPN及PVC共混物的合成与表征

Ⅰ. 增韧环氧／聚氨酯互穿网络聚合物的合成与表征 用部分环氧树脂与丁腈羧反应，进行端基转化，制得端环氧基丁腈－环氧共聚物与环氧树脂的混合物，经叔胺固化后，得到增韧环氧（TEpx）。制备了两种IPN体系，体系1为增韧环氧／蓖麻油聚氨酯IPN，体系2为增韧环氧／聚醚聚氨酯IPN。用红外光谱研究了动力学，研究结果是，对于体系1，－OH基与－NCO基的反应速度大于环氧基的聚合速度，因此，IPN体系中，PU网络的形成比环氧网络快。环氧上的－OH基与蓖麻油上的羟基相似。同属伸羟基，它也会与－NCO基反应，因此，所形成的IPN的两网络间，存在着一定程度的化学交联。在增韧环氧的分子结构中，含有丁腈羧低聚物链段，使得增韧环氧与蓖麻油聚氨酯的相容性较好，该因素对这种IPN形态结构的形成，是很重要的，从动态力学性能的测试结果，能说明这个问题，即玻璃化转变峰很宽，在一定组成时，半峰宽几乎达100 ℃。对于体系2，聚氨酯相起反应的羟基是伯羟基，它与－NCO基的反应速度比环氧中的羟基与－NCO基的反应速度大得多。此外，体系中的两组分，即增韧环氧与聚醚聚氨酯的相容性不好，反应速度的差别与相容性的差别，均将导致反应体系中相分离程度的增大。这在tanZ-T曲线上表现得很明显，出现了两个相距甚远的玻璃化转变峰。利用透射电子显微镜对两个IPN体系进行了形态观察，这些IPN具有特殊的结构，既有增韧环氧所存在的两相结构，又有IPN的两相结构。Ⅱ. 聚氯乙烯－丁腈羟低聚物共混物的合成与表征 制备了高聚物（PVC）－低聚物（HTBN）共混物，研究了该共混物的力学性能，阻尼性能及形态结构。研究结果表明，在HTBN中，丙烯腈含量较高时，随着HTBN加入量的增加，PVC的阻尼峰均有不同程度的加宽加高。在力学性能方面，共混物的抗张强度、伸长率也随低聚物中丙烯腈含量的高低而变化，丙烯腈含量较高时（25％，36％），随HTBN加入量的增加，性能变化不大，而丙烯腈含量较低时（15％，5％），当HTBN的加入达一定量时，性能发生突降。这些现象的出现，主要与相容性有关，HTBN中丙烯腈含量高，极性大，与PVC混溶性好，因而阻尼性能、力学性能均好。而HTBN中丙烯腈含量低，与PVC之间的粘合力不好，即混溶性不好，因而共混物性能不好。由TEM照片看，该共混体系的形态结构为细胞状结构，细胞内存在着界面模糊的两相结构，在低丙烯腈含量（15％）时，存在着部分界面清晰的两相结构，形态观察的结果与性能测定的结果一致。

Evaluation of both composition and strain distributions in InGaN epitaxial film using x-ray diffraction techniques

The composition and stain distributions in the InGaN epitaxial films are jointly measured by employing various x-ray diffraction (XRD) techniques, including out-of-plane XRD at special planes, in-plane grazing incidence XRD, and reciprocal space mapping (RSM). It is confirmed that the measurement of (204) reflection allows a rapid access to estimate the composition without considering the influence of biaxial strain. The two-dimensional RSM checks composition and degree of strain relaxation jointly, revealing an inhomogeneous strain distribution profile along the growth direction. As the film thickness increases from 100 nm to 450 nm, the strain status of InGaN films gradually transfers from almost fully strained to fully relaxed state and then more in atoms incorporate into the film, while the near-interface region of InGaN films remains pseudomorphic to GaN.

CHANNELING ALIGNMENT FOR EPITAXIAL LIGHT-MASS FILM ON HEAVY-MASS SUBSTRATE

A simple procedure for obtaining a background-free backscattering spectrum of a light-mass film on a heavy-mass substrate by a normal incidence/grazing exit geometry has been described. Using this method such films can be aligned rapidly and accurately, and the impurity or defect information on the films can be obtained without need for realignment. Example is given from MeV Li-3+ analysis of a deposited film of Si on a single crystal substrate of yttria-stabilized, cubic zirconia.