大口径干涉仪系统传递函数校准

 波前功率谱密度(PSD)被用于评价ICF激光驱动器光学元件在中频区域的波前误差。目前主要采用大口径相移干涉仪检测ICF光学元件的波前畸变，通过付立叶变换获得波前的PSD分布。相移干涉仪在较高空间频率分量的测量上存在失真效应，因此需对干涉仪的空间频率传递函数进行校准。本文采用位相比较法测量大口径相移干涉仪的系统传递函数。我们采用衍射光学元件的制造工艺，设计、制作了标准的透射和反射位相元件，比较理论计算值与实测PSD值，分别获得了大口径相移干涉仪透射、反射测量模式的系统传递函数。

The calibration of the system transfer function for large interferometer

The wavefront power spectral density (PSD) is being adopted for specifying the large optical components employed in high power density solid state laser for inertial confinement fusion (ICF). The phase wavefront detected by the interferometer is digitally processed to create the one dimension wavefront PSD. There're anamorphic effects for measuring the wavefront's components with high spatial frequencies. It's necessary to calibrate the system transfer function of the interferometer. Based on the principle of phase comparing, we have designed and fabricated a 100 mm diameter standard phase object that contained a step phase. The system transfer functions of the transmitted measuring mode and the reflective measuring mode for the WYKO 24 inch interferometer have been respectively obtained by comparing the theoretical values and the measured value of the PSD. The analysis and the experimental result are discussed in this paper.