液晶自适应光学系统中控制矩阵的精确测量  

Accurate measurement of control matrix in liquid crystal adaptive optical system

作　　者：刘超[1,2] 孔宁宁[1,2] 胡立发[1] 宣丽[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室,吉林长春130033 [2]中国科学院研究生院,北京100039

出　　处：《光学精密工程》2009年第12期2899-2905,共7页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.60736042;No.50703039;No.60578035);吉林省与中科院科技合作项目(No.2008SYHZ0005)

摘　　要：为了提高自适应光学系统的校正精度,提出了一种新的通过改变测量响应矩阵时的调制波长来准确计算控制矩阵的方法。首先,测量去除平移项的前35项Zernike模式在不同调制波长下的实际光波位相调制曲线。然后,对每个调制波长,依次计算相对于原点的位相调制曲线,最终找到一个与实际光波位相调制曲线斜率相差最小的位相调制曲线。其所对应的调制波长,就是测量响应矩阵时,在相应的Zernike模式下应该施加在液晶波前校正器上的调制波长。这样,对于35个Zernike模式,便可以找到35个调制波长。最后,对每个Zernike模式,即响应矩阵的每一列对相应的调制波长进行归一化,最终得到准确的控制矩阵。实验表明,采用此方法液晶自适应光学系统的校正精度由73%提高到了95%以上,校正误差为常规方法的1/5,且此比例与系统的最大畸变补偿位相的大小无关。结果表明此方法极大地提高了液晶自适应光学系统的校正精度。In order to improve the correction accuracy of Liquid Crystal Adaptive Optical Systems （LCAOS）, a new method of measuring the control matrix by changing the modulated wavelength is proposed. Firstly, the actual phase modulation lines of the first 35 Zernike modes are measured under a series of modulated wavelengths. And then the phase modulation lines o{ each modulated wavelength relative to the origin point are calculated, and one of the phase modulation lines can be found whose slope is the closest to the actual phase modulation line and whose corresponding modulated wavelength is the one that must be applied on the liquid crystal wavefront corrector when the response matrix is measured. With this method, 35 modulated wavelengths can be obtained corresponding to 35 Zernike modes. Finally, each column of response matrix by modulated wavelength is normalized, and an accu-rate control matrix is obtained. Experimental results indicate that the correction accuracy of the system with the new method has improved from 73% to 95% and the residual compensated error is only 1/5 of that with the normal method, meanwhile the coefficient is not related to the maximum compensated phase. It is shown that the new method greatly improves the correction accuracy of the LCAOS.

关 键 词：液晶自适应光学系统 响应矩阵 控制矩阵 校正精度 

分 类 号：O753[理学—晶体学] TH703[机械工程—仪器科学与技术]