宽波段高分辨率改进型Czerny-Turner成像光谱仪研究

主要针对Czerny-Turner结构在成像光谱仪系统中的应用进行了研究。Czerny-Turner结构主要存在的像差为像散。为了获得了该结构的完善消像散条件，对其进行了理论分析和结构改进。系统的基本结构不变，仍由球面准直镜，平面光栅和球面聚焦镜组成，但在聚焦镜后添加了一个带楔角的柱面镜，该柱面镜解决了子午方向和弧矢方向上存在大像散差的问题，使系统可以在较宽的波段上实现较高的分辨率，同时元件制作成本大大降低。设计了一个工作在可见光波段(380~760 nm)的改进型成像光谱系统，并对设计理论进行了验证。例子成功设计了数值孔径0.05，全视场全波段调制传递函数值在奈奎斯特频率(20 lp·mm-1)下大于0.59的高分辨率成像光谱仪光学系统。这种改进的系统设计理论适用于小型宽波段高分辨率成像光谱仪。

Study on the Advanced Czerny-Turner Imaging Spectrometer with High Resolution in Broadband

This paper studies the Czerny-Turner optical structure which is used for the application in imaging spectrometers. To obtain the perfect astigmatism-corrected condition, the Czerny-Turner system has been analyzed and advanced. The basic structure of optical system is still as the traditional form which is composed by the spherical collimating mirror, the plane grating and the spherical focusing mirror. However, an off-the-shelf cylindrical lens is added after the focusing mirror to remove astigmatism differences between the tangential direction and the sagittal direction. It makes the advanced optical system presents high resolution over the full bandwidth and decreases the cost. An example of the imaging spectrum system in the waveband of 380~760 nm has been designed to prove our theory. A system owns that NA equals to 0.05, and the modulation transfer functions (MTF) of all fields of view are more than 0.59 over the broadband under the required Nyquist frequency (20 lp·mm-1). It certificates that the optical system theory can be applied to the small scale imaging spectrometer with high resolution in spectral broadband.