Zhang Zhiyu, Wang Ruoqiu, Hao Teng, Guo Chengli, Xue Donglin, Zhang Xuejun
Appl Opt. 2018 Dec 1;57(34):F31-F36. doi: 10.1364/AO.57.000F31.
With the development of optical systems used in astronomical and earth observation, aspherical and free-form surfaces are increasingly used because they are lightweight and have improved image quality. As a highly accurate, aberrationless technique, computer-generated hologram (CGH) plays an important role in wavefront testing. At present, the main way to fabricate phase CGH is reactive ion etching, which suffers from low accuracy. To improve the accuracy, physical vapor deposition (PVD) is applied in the fabrication of phase CGH. The wavefront errors of PVD-fabricated phase CGH were analyzed. Testing results indicate that the wavefront error of the CGH is 0.020λ root mean square (RMS), mainly caused by the machine tool orthogonality error rather than the PVD process. The diffraction efficiency of the +1st order is 22.4%.
随着用于天文观测和地球观测的光学系统的发展，非球面和自由曲面因其重量轻且图像质量得到改善而越来越多地被使用。作为一种高精度、无像差技术，计算全息图（CGH）在波前测试中发挥着重要作用。目前，制作相位CGH的主要方法是反应离子刻蚀，但该方法精度较低。为了提高精度，物理气相沉积（PVD）被应用于相位CGH的制作中。对PVD制作的相位CGH的波前误差进行了分析。测试结果表明，CGH的波前误差为0.020λ均方根（RMS），主要是由机床正交误差而非PVD工艺引起的。+1级衍射效率为22.4%。
