相变材料具备良好的光热稳定性和可擦写特征，其在相变前后存在光学参数的明显变化，通过施加不同参数的激光激励能够实现对相变材料晶化状态的精确调控。由此，在相变材料不同晶化状态呈现不同光学参数的基础上，提出一种多阶折射率调制的薄膜平板透镜。以典型相变材料Ge₂Sb₂Te₅作为光调制介质，对介质薄膜的晶化状态开展多阶和多区域的离散控制以满足理论上聚焦透镜所需的相位约束。完成具有多种数值孔径的平板透镜的设计，并通过有限差分时域方法和Zemax分别分析透镜聚焦的参数指标，检验了平板透镜的成像性能。

全息三维显示具有呈现包含真实物体所有特征的三维场景的能力，这对信息的数据量和分辨率提出了极高的要求。体全息术可以为高分辨率三维显示提供大容量数据存储和基于三维布拉格光栅的实现方式。提出体全息三维显示方法，通过计算全息算法得到三维物体的全视差相息图，由相位型空间光调制器对物光波进行波前编码，利用体全息光栅的角度选择特性在光致聚合物的同一全息图基元中复用多幅全息图。在参考光照射下，可以重建出多角度的三维场景，扩充了三维显示的空间带宽积。

The effect of the diminution of the sensitizing intensity from initially high value on two-center recording is experimentally and theoretically investigated. A linear diminution of the sensitizing intensity is designed, and three different diminution rates are employed for the experimental investigation. The results show that the dynamic range can be improved by reducing the diminution rate of the sensitizing intensity. Compared with that of traditional two-center recording, the recording sensitivity obtained in the experiment is more improved when the maximum dynamic range is achieved. The effect of the diminution of the sensitizing intensity on grating uniformity and the effect of the initial sensitizing intensity on the recording sensitivity are theoretically investigated.

Fulgide, a kind of thermally irreversible photochromic compound, can be used for polarization holographic recording owing to its photoinduced anisotropy and photochromic property under the irradiation of linear polarization light. In this letter, a new technique of optical image operation based on the polarization multiplexing scheme in the fulgide film is demonstrated, which can implement the readout of two individual orthogonal polarized images separately and the subtraction or summation of the two images by simply rotating a polarizer in front of the charge-coupled device (CCD) detector.

The phase shifts of the extinction and refractive index gratings to the illumination pattern are revealed in doped polymethyl methacrylate (PMMA). The dynamic process of these shifts is studied via two-wave coupling at 351 nm. It is shown that these shifts are from the strain and the shrinkage inside the sample and accompanied with the photo-repolymerization process during the building process of the holographic grating. Such shifts will cause obvious energy exchange between the two recording beams and enough attention should be paid to the nonlocal property of the holographic gratings of the material in the application.

2 Nonvolatile two-color holographic recording gated by incoherent ultraviolet (UV) light centered at 365 nm is investigated in near-stoichiometric lithium niobate crystals. The influence of thermal treatment on the two-color recording is studied. The results show that thermal reduction tends to improve the two-color recording performance, whereas thermal oxidation degrades the two-color recording. With an incoherent 0.2-W/cm2 UV gating light and a 0.25-W/cm2 semiconductor recording laser at 780 nm, a two-color recording sensitivity of 4\times10^{-3} cm/J and a recording dynamic range characterized by M/# of 0.12 are achieved in a 2.2-mm thermally reduced near-stoichiometric lithium niobate crystal. We attribute the improvement to the prolonged lifetime of small polarons and the increased absorption at the gating wavelength due to thermal reduction.

Photo-induced processes in organic materials mostly occur on molecular levels. Excited molecules may split to form radicals, starting a polymerization process with diffusing monomers. The azo-dyes perform an optically induced cis-trans isomerization. During pattern formation like a holographic grating, the local temperature increase, especially in thin films, is up to date a subject of estimation from absorption and dissipation data. However, the exact knowledge of the surface temperature would help a lot in understanding the resulting refractive index and thickness patterns during holographic exposure. In this paper, in-situ pyrometer measurements are presented. As examples, different photosensitive materials, varying from a photopolymer to polycrystalline azo dyes, are used in order to outline the magnitude of this effect and demonstrate the feasibility of this technique.