Yoo Byung-Wook, Megens Mischa, Sun Tianbo, Yang Weijian, Chang-Hasnain Connie J, Horsley David A, Wu Ming C
Opt Express. 2014 Aug 11;22(16):19029-39. doi: 10.1364/OE.22.019029.
We report on microelectromechanical systems (MEMS)-actuated 32 × 32 optical phased arrays (OPAs) with high fill-factors and microsecond response time. To reduce the mirror weight and temperature-dependent curvature, we use high-contrast-grating (HCG) mirrors comprising a single layer of sub-wavelength polysilicon gratings with 400 nm thickness, 1250 nm pitch, and 570 nm grating bar width. The mirror has a broad reflection band and a peak reflectivity of 99.9% at 1550 nm wavelength. With 20 × 20 μm2 pixels and 2 μm, the OPA has a total aperture of 702 × 702 μm2 and a fill factor of 85%. The OPA is electrostatically controlled by voltage and has a total field of view of ± 2°, an instantaneous field of view (beam width) of 0.14°, and a response time of 3.8 μs. The latter agrees well with the mechanical resonance frequency of the HCG mirror (0.42 MHz).
我们报道了具有高填充因子和微秒级响应时间的微机电系统（MEMS）驱动的32×32光学相控阵（OPA）。为了减轻反射镜重量并降低与温度相关的曲率，我们使用了高对比度光栅（HCG）反射镜，其由单层亚波长多晶硅光栅组成，厚度为400 nm，间距为1250 nm，光栅条宽度为570 nm。该反射镜具有较宽的反射带宽，在1550 nm波长处的峰值反射率为99.9%。该OPA的像素为20×20μm²，间距为2μm，总孔径为702×702μm²，填充因子为85%。该OPA通过电压进行静电控制，总视场为±2°，瞬时视场（波束宽度）为0.14°，响应时间为3.8μs。后者与HCG反射镜的机械共振频率（0.42 MHz）非常吻合。
