反射镜平动式光栅光调制器的光学特性分析

Optical Performance Analysis and Simulation of Reflector Moving Grating Light Modulator

提出了一种反射镜平动式光栅光调制器,每个像素主要由一个可动反射镜和上面的固定光栅组成,通过控制可动反射镜和固定光栅的距离达到对入射光的调制·依据标量衍射理论对反射镜平动式光栅光调制器工作状态的光学特性进行了详细的理论分析;并仿真了光调制器的结构参量对衍射效率和对比度的影响·发现:当可动平板和光栅的距离为λ0和5λ0/4,像素表现为暗态和亮态;这种光调制器的工作原理决定了其有效面积大,具有形成面阵的潜力;固定光栅占空比为1/2时,对比度最优;同时给出了对比度随入射光带宽的关系,即带宽越大,对比度急剧下降·

A novel spatial light modulator called reflector moving grating light modulator is proposed. Each pixel mostly consists of a fixed grating and a movable reflector. The optical performance of this modulator is a key parameter, so it is necessary to analyze the optical performance. With scalar diffraction theory, its optical performance is analyzed in details. Meanwhile, computer simulation is carried on, and the influence of several key parameters on the diffraction efficiency and contrast ratio is presented. All these results indicate that the height between the fixed grating and movable reflector must be controlled at λo in off state, 5λo/4 in on state respectively, and the occupation ratio of the fixed grating has an important influence on the optical performance whose optimized value is 0.5. The contrast ratio at different wavelength width is given out, wider wavelength, worse contrast ratio.