通过计算MEMS微变形镜校正畸变波面后的残余误差,研究不同单元间耦合情况对变形镜校正效果的影响.针对连续镜面MEMS微变形镜单个致动器单元工作时,相邻及以外的单元都会有一个变形量,用耦合系数来表征单元工作时对相邻单元变形量的影响程度.以单元间距为3mm的10×10单元阵列MEMS微变形镜为例,研究了变形镜校正不同畸变波面时,最佳耦合系数与波面畸变因素对应关系.当校正对象为前20阶Zernike多项式波面,此变形镜的最佳耦合系数为10%.分析了单元间距分别为2,2.5,3,3.5,4mm时,10×10单元阵列MEMS微变形镜校正效果的变化情况;不同单元间距对应的最佳耦合系数分别为12%,11%,10%,9%,8%.
Based on the correction of the residual error of wave-front correction,the relationship between the coupling of actuators and correction capability of MEMS-based deformable mirror(DM) is analyzed.When a single actuator of the continuous surface DM works,it creates a displacement at the other actuators,which is described using coupling coefficient(cc).For a MEMS-based DM with a 10×10 actuator array,with the distance between two adjacent actuators(b) being 3 mm,correcting the first 20 Zernike modes,the best coupling coefficient is 10%.Different distances between two adjacent actuators(b) correspond to different correction capabilities and different coupling coefficients.Corresponding to b of 2,2.5,3,3.5,and 4 mm,the best coupling coefficient of the DM is 12%,11%,10%,9%,and 8%,respectively.