Opt Lett. 2018 Jun 15;43(12):2815-2818. doi: 10.1364/OL.43.002815.
Permanent gratings are recorded in planar-aligned dye-doped nematic liquid crystal cells under visible light illumination. By increasing the irradiation intensity and exposure time, several diffraction orders of the recorded gratings are obtained in the Raman-Nath diffraction regime. By applying a dynamic transverse shear on one of the confining plates of the cell, an enhancement of the diffraction efficiency is achieved, which follows the period of the grating. By microscope inspection under static displacement of the upper plate, surface gratings formed by the dye adsorption are revealed in both the front and rear windows of the cell, indicating that the diffraction amplification originates from a coherent superposition of the diffracted orders when the gratings are displaced half a period. The effect provides self-matched amplification of diffraction with a simple cell, a single photo-inscription stage, and elementary displacement steps.
永久性光栅是在可见光照射下在平面排列的掺杂染料向列液晶盒中记录的。通过增加辐照强度和曝光时间，可以在喇曼-纳斯衍射区获得记录光栅的多个衍射级。通过对盒体的一个约束板施加动态横向剪切，可以实现衍射效率的增强，其增强幅度与光栅的周期一致。通过显微镜在平板静态位移下进行检查，在前窗和后窗中都发现了由染料吸附形成的表面光栅，这表明当光栅位移半个周期时，衍射级的相干叠加导致了衍射的放大。该效果提供了简单的盒体、单一的光记录阶段和基本的位移步骤的自匹配衍射放大。
