液晶光栅自干涉测量空间光调制器相位调制特性  

Self-Interference for Spatial Light Modulator Phase Modulation Characteristics by Liquid Crystal Grating

作　　者：赵自新[1] 肖昭贤 张航瑛 赵宏[1] 

机构地区：[1]西安交通大学机械工程学院机械制造系统国家重点实验室,陕西西安710049

出　　处：《激光与光电子学进展》2017年第6期140-146,共7页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(61575157);中国博士后科学基金(163576)

摘　　要：提出了一种测量平行液晶空间光调制器(SLM)相位调制特性的自干涉法。该方法实验简单,具有良好的稳健性。加载到SLM的灰度图由三部分组成,一部分是二元衍射光栅灰度图;另外两部分加载的灰度图均匀分布,下部分灰度值恒为0,上部分灰度值从0逐渐增加。随着上部分灰度的改变,经过相位调制的反射光束与光栅产生的+1级衍射光干涉生成一整幅错位条纹图,通过测量同一幅干涉条纹的周期和上下条纹之间的相对移动量来计算SLM的相位调制量大小,该方法消除了环境振动或空气湍流引起的条纹抖动对测量的影响,提高了测量精度。与其他方法相比,该方法获取SLM相位调制特性不需要复杂的光学装置,且具有优良的机械稳定性,反应快速更易实施。A self-interference method for measuring phase modulation characteristics of parallel liquid crystal spatial light modulator （SLM） is proposed. The method is experimentally simple and robust. The gray image loaded onto the SLM is composed of three parts, one is a binary diffraction grating grayscale map, the other two maps are codified by a uniformly distributed gray level area, where the gray value below the part is constantly 0, the upper part gray value is gradually increased from O. With the gray value of the upper part changing, the reflected beam by modulation interferes with the q-1 order grating diffraction wave to generate a whole dislocation fringes, the amount of SLM phase modulation can be calculated by measuring the cycle and the relative displacement between the upper and lower fringes on the same interference pattern. This proposed method eliminates the influence of the fringe jitter caused by ambient vibration or air turbulence on the measurement and improves the measurement accuracy. Compared with other methods, the new method which obtains the phase modulation characteristics of SLM does not require complex optical devices, and has excellent mechanical stability, fast response and easy to implement.

关 键 词：测量 液晶空间光调制器 自干涉法 相位调制特性 图像后处理 

分 类 号：O436[机械工程—光学工程]