论文部分内容阅读
利用表面工艺制作的微机电系统(MEMS)变形镜具有体积小、分辨率高、驱动电压低等优点,然而镜面存在大量的释放孔形成一个规则的阵列结构,影响了变形镜的光学性能。设计制作了一种基于表面工艺的MEMS变形镜单元,研究了释放孔阵列对变形镜光学性能的影响。从夫琅禾费衍射原理出发,建立了二维释放孔阵列的衍射理论模型。研究结果表明,随着释放孔尺寸的增加和相邻释放孔间距的降低,中央零级衍射光强降低,衍射效应增强;同时镜面的有效反射面降低,总反射率降低。释放孔结构影响哈特曼波前传感器对畸变波前的测量性能,使聚焦光斑能量降低,同时随着波前扰动的增强,相邻聚焦光斑发生串扰,波前测量精度降低。
Micro-electromechanical system (MEMS) deformable mirrors fabricated by surface technology have the advantages of small volume, high resolution and low driving voltage. However, there are a large number of release holes in the mirror to form a regular array structure, which affects the optical performance of the deformable mirror. A MEMS deformable mirror unit based on surface technology was designed and fabricated. The effect of the array of holes on the optical performance of the deformable mirror was studied. Based on the principle of Fraunhofer diffraction, a diffraction theoretical model of a two-dimensional pore array was established. The results show that with the increase of the size of the release hole and the decrease of the distance between the adjacent release holes, the central zero-order diffraction intensity decreases and the diffraction effect increases. Meanwhile, the effective reflection surface of the mirror decreases and the total reflectivity decreases. The structure of the release hole affects the measurement performance of the Hartmann wavefront sensor on the distortion wavefront and reduces the energy of the focused spot. Meanwhile, as the wavefront perturbation increases, crosstalk occurs at the adjacent focused spots and the accuracy of the wavefront measurement decreases.