双压电片变形反射镜作为波前校正器具有结构简单、变形量大、成本低及制造周期短的优点, 能代替传统分立式变形镜从而降低自适应光学系统的成本。为验证工艺的可行性和了解双压电片变形反射镜的性能, 制造了一块20单元的试验样镜。样镜采用了双层压电陶瓷的结构, 其中一层作整体离焦电极以校正大幅值的离焦像差。利用Veeco干涉仪测量了样镜单元电极影响函数, 分析了其对前36项Zernike像差的校正能力。结果表明, 样镜对离焦像差能获得高达8 μm以上的校正量, 对其它高阶像差也能适量校正, 但校正能力随空间频率升高而降低, 显示出其适合校正低阶像差的特性。此外, 讨论了不同有效孔径下样镜对Zernike像差的拟合能力。

Compared with conventional stack actuator deformable mirrors, the bimorph deformable mirrors have more simple structures, larger stroke, lower cost and less time consumption. Therefore, they are potential substitutes of stack actuator deformable mirrors in adaptive optics systems. A prototype of 20-element bimorph deformable mirror is designed and fabricated in order to verify the process and investigate its basic characters. This prototype has two PZT layers, the outer one is divided into 19 electrodes, and the inner one has a whole defocus electrode. The influence functions of the fabricated prototype are measured by using a Veeco interferometer and the correction ability for the first 36 Zernike aberrations is simulated. The results show that it has a good fitting ability for low order Zernike aberrations, especially for defocus, and it achieves an amplitude more than 8 μm. And this ability decreases as the increase of space frequency, which indicates that this bimorph deformable mirror is very suitable for correcting low order aberrations. In addition, fitting abilities of the fabricated prototype for correcting Zernike aberrations with different clear apertures are discussed.