基于空间光调制器的三维相位全息图再现像优化

Optimization of reconstructed images of 3-D phase hologram based on phase-only spatial light modulator

在现有的二维图像再现效果改善方法的基础上,对三维物体再现像质量提高的方法进行研究。基于衍射理论,分析了具有有限填充因子空间光调制器的栅格结构对重构图像质量的影响。编入双线性相位因子到纯相位全息图,使得有效光偏移中心光轴传播,让图像细节得到完整重构再现。然后迭加双会聚球面波相位因子,使得各再现像面与空间光调制器栅格结构引起的多级衍射光聚焦平面的位置进行分离,利用光阑和空间滤波器共同作用来消除高级衍射光以及零级光对重构图像质量的影响。搭建了基于LC-SLM的相位全息图光电再现系统用于实验验证。实验结果表明三维物体再现像质量得到明显的提高。

Based on the existed ways of 2-D reconstructed images by spatial light modulator （SLM）, the methods to enhance the reconstructed quality of 3-D images are investigated. Based on the diffraction theory, the effects of a lattice SLM with a limited fill factor on the reconstructed images are analyzed. The effective light is moved away from the center optical axis by coding the double linear phases into the phase-only hologram, so the details of the original patterns can be reconstructed completely. The two focused planes of reconstructed images and the multi-order beams caused by the lattice structure of the SLM can he separated spatially, through adding the phases of doubleconvergent spherical wave. The spa- tial filter is used to eliminate the influences of higher-orders diffraction beams and zero-order light of reconstructed ima- ges, respectively. A holographic optoelectronic display system based on liquid crystal spatial light modulator （LC-SLM） is set up to demonstrate this method.