用于平板波导显示的反射型体全息光栅制备

Preparation of Reflective Volume Holographic Grating for Plate Waveguide Display

基于对全息平板波导显示系统中核心全息光学元件的研究,采用双光束干涉法和相应的后处理工艺,在以石英玻璃为基底、重铬酸盐明胶为记录介质的全息干板上制备了具有折射率调制的反射型体全息光栅,并研究了不同曝光强度、折射率调制度、水洗时间对光栅衍射效率的影响。实验结果表明,经441.6 nm的He-Cd激光光源记录以及复杂的后处理工艺,最终制备的反射型体全息光栅衍射效率最高可达到61.8%,在可见光入射条件下产生了明显的分光效果。制备的全息实验样片在满足全反射的前提下可进行波导传输,为提高头戴式设备和增强现实等显示设备在传输过程中的衍射效率提供了一种新方法。

By studying the core holographic optical elements in the holographic plate waveguide display system,we prepare a reflective volume holographic grating with refractive index modulation on a holographic plate with quartz glass as substrate and dichromate gelatin as recording medium.The effects of different exposure intensity,refractive index modulation and water washing time on diffraction efficiency of grating are researched.Experimental results show that the diffraction efficiency of reflective volume holographic gratings can be improved by using 441.6 nm HeCd laser light source and complex post-treatment process.The diffraction efficiency of reflective volume gratings can reach 61.8%.Under the condition of visible light incident,a remarkable light splitting effect is produced.The prepared holographic experimental sample can be transmitted by waveguide under the condition of total reflection,which provides a method to improve the diffraction efficiency of display devices such as head mounted display device and augmented reality during transmission.