913单元变形镜性能测试与分析

为了满足自适应光学系统校正高阶像差和在低温环境下正常使用的要求，研制了一块913单元的分立式连续表面变形镜。利用?300mm口径Veeco干涉仪对变形镜的部分静态性能进行了面形影响函数测量、面形展平测试和Zernike像差拟合测试，并利用4-D动态干涉仪测量了变形镜从20℃~-10℃的面形。结果表明，913单元分立式连续表面变形镜各驱动点的最大变形量为±3.5μm，相邻驱动器之间的交连值为9.3%；展平后的镜面面形波峰波谷值为66.0nm，均方根值为5.0nm；913单元变形镜对Zernike多项式的拟合能力达到了设计要求；变形镜的低温镜面变形不影响系统的正常使用。该913单元变形镜能够满足自适应光学系统的实际使用要求。

Performance test and analysis of 913-element deformable mirrors

In order to correct high order aberration for an adaptive optics (AO) system and make it operate normally at cryogenic temperature, a 913-element discrete actuators continuous facesheet deformable mirror (DM) was developed. A Veeco interferometer in ?300mm diameter was used to examine partial static performance of the deformable mirror:the influence function of an individual actuator, flattening test and the correction capability of the deformable mirror about Zernike aberrations fitting. The surface of DM from 20℃ to -10℃ was measured by a 4-D dynamic interferometer. The testing results show that the max correction ability of the deformable mirror actuated by an individual actuator is ±3.5μm. The distance between the neighbor actuators is 9.8μm and the coupling between the neighbor actuators is 9.3%. The surface of the deformable mirror after flattening is really smooth, of which the PV is 66.0nm and the RMS is 5.0nm. The fitting capability of the Zernike polynomials of the 913-element deformable mirror satisfies the demand of the adaptive optics. The thermally induced surface deformation didn't influence the performance of DM at low temperature. According to these tests, the 913-element deformable mirror satisfies the actual demands of the adaptive optics system.