新型圆二色光谱测量及偏振操控图像研究

In this project, new-type spectral measurement of circular dichroism and polarization-controlled images will be carried out based on the unique polarization diffraction properties of polarization holographic gratings. First, cycloidal optical axis gratings with high diffraction efficiency and stable performance are prepared by using orthogonal circularly polarized coherent superposition and optical-induced liquid crystal alignment. Second, the spectral measurements of circular dichroism and device designs based on the polarization holographic diffraction method are developed to replace the traditional polarization modulation and wavelength scanning technique. The amplitudes of the ±1 order diffraction light of the cycloidal optical axis grating are proportional to the right-handed and left-handed circular polarization component of incident light, respectively. According to the measurement of the absorption rate difference after the left-handed and right-handed circular polarization light passing through the tested sample, the real-time measurement of circular dichroism spectral data are realized based on the simultaneous acquisition of diffraction signals for different wavelength light. Then, two-dimensional polarization holographic gratings are recorded by two superimpositions with orthogonal linear polarized lights and two orthogonal circularly polarized lights in azobenzene liquid crystal thin film. The device for measuring polarization is designed based on the simultaneous acquisition of the four first-degree diffraction signals of two-dimensional polarization grating and the study on the real-time measurement of Stokes parameter of light polarization is developed. Finally, polarization-controlled image storage and display is carried out based on the polarization modulation and polarization conversion of the overlapped polarization grating recorded by doubled-exposure with orthogonal circular polarization superposition. The expected results will provide data reference for spectral measurements of circular dichroism and multifunctional diffractive-optical device.

项目基于偏振全息光栅独特的偏振衍射行为开展圆二色光谱测量和偏振操控图像的研究。首先，利用正交圆偏光相干叠加和液晶光控取向制备衍射效率高性能稳定的摆线型光轴光栅。其次，取代传统的偏振调制和波长扫描方式，基于摆线型光轴光栅衍射开展圆二色谱测量方法和器件设计研究。摆线型光轴光栅的±1级衍射振幅正比于入射光的右旋和左旋圆偏振分量，依据左右旋圆偏光经过样品后的差分吸收，通过对每个波长衍射信号的同时采集实现圆二色谱数据的实时测量。然后通过正交线偏光和圆偏光的两次叠加记录，利用光致各向异性材料制备二维偏振全息光栅，基于对二维偏振光栅四个±1级衍射信号的同时测量设计偏振测量器件，开展偏振光Stokes参量测量方法研究。最后，通过正交圆偏光叠加的两次曝光记录，利用叠置偏振全息的偏振转换及衍射效率的偏振依赖关系，开展偏振控制的图像存储与显示研究。预期结果希望对圆二色谱测量和多功能衍射光学器件研制提供数据参考。

项目基于偏振全息光栅独特的偏振衍射行为开展圆二色性光谱测量和偏振操控图像的研究，实现了性能稳定多功能摆线型光轴光栅制备、全光控制光束分束、双光子光栅记录及偏振控制图像存储与显示。主要内容包括：1）利用偏振敏感的光致各向异性记录介质，基于偏振全息方法在偶氮液晶聚合物薄膜上记录多种类型的偏振全息光栅，通过考察记录光栅的偏振变换、衍射效率、衍射带宽及热稳定性制备多功能衍射光学元件，并实现了圆二色谱测量和偏振态的调制。2）基于偶氮分子的光致异构和光致取向效应，利用空间自相位调制方法研究了偶氮掺杂液晶的非共振光学非线性效应、瞬态光栅特性及光致光栅的衍射增强效应。3）利用偏振全息光栅设计并论证了一种三维显示系统、全光逻辑序列发生器、增强现实显示方案。项目实施期间发表SCI学术论文15篇，申请发明专利3项。预期结果希望对偏振操控和测量，制备多功能衍射光学器件提供数据参考。