复杂分光仪器中的像差研究

Aberrations in Complex Spectral Instruments

为提高分光仪器的性能,采用两个椭球面镜和一个椭球面消像差光栅分光。光源发出的光线被第一个椭球面镜反射,产生特定的波前,经过光栅衍射以后,不同波长的光波被第二个椭球面镜汇聚到探测器的不同位置上。系统具有复杂的像差特性和成像特性,根据费马原理,参考第二代全息变线距光栅的制作光路和理论,建立坐标系,定义两个椭球面上的入射角和反射角,确定各元件的位置变量,确立基本几何关系,将光程函数分为两部分:由衍射引起的光程变化和几何位置引起的光程变化,将两部分都按级数展开,给出了高阶像差的解析形式。对于平面、柱面、球面光栅和反射镜也可以使用这些公式。像差的解析式和光路也可以用于各种分光仪器中。

To improve the quality of the spectral instruments, two ellipsoidal mirrors and an ellipsoidal aberrationreduced grating are used. Reflected by the first ellipsoidal mirror, the wave front of the light is changed, and after passing the grating the light is focused on different positions of the detector according to the difference of the wavelength by the second mirror. The spectral instruments are with complex aberration and imaging characteristics. According to Fermat principle, consulting the second generation varied-line-space gratings fabrication optical layout and theory, the coordinate system is setup, the angles of incidence and reflection are defined, the elements are located, and the basic geometrical relation is established. The optical path function is divided into two parts： one is associated with the diffraction, and the other is associated with the optical path change by the geometrical position. After the power series of the above two optical path are expanded, the analytical expressions of the high-order aberration are derived, which are useful in the plane, cylinder, spherical gratings, as well as reflector. And the expressions of the aberrations and the optical layout can be used in other spectral instruments.