Imaging spectrometer beam splitting system based on free-form surface

Abstract

The invention discloses an imaging spectrometer beam splitting system based on a free-form surface. The system is composed of an entrance slit, a free-form surface collimation reflector, a plane diffraction grating, a free-form surface imaging reflector and an image surface detector. The imaging spectrometer beam splitting system is characterized in that the high-freedom-degree non-rotation-symmetrical free-form surface is used in cooperation with the plane grating which is high in performance and mature in technology, and the beam splitting system which is simple and compact in structure, low in aberration, low in distortion and high in efficiency is realized. In the system, the mode that the hole diameter deviates from the axis is adopted to achieve the purpose of no light obstruction, relative angle rotation does not exist among all optical elements, installation and adjustment can be realized conveniently and easily, and the development time can be shortened. The beam splitting system based on the free-form surface realizes good spectral imaging at the 8-12.5-micrometer long wave infrared spectrum, and on the premise that it is guaranteed that the system is simple and compact, spherical aberration, comatic aberration, astigmatism, spectral distortion, spectral line bending and the like are well corrected. The imaging spectrometer beam splitting system can be applied to the field of aerospace and aviation hyperspectral imaging.

Description

technical field [0001] The present invention belongs to the field of imaging spectrometer design, and specifically relates to a novel optical design of a plane grating spectroscopic system based on a free-form surface. The spectral band of the embodiment of the present invention is long-wave infrared, and it is also applicable to other fields such as visible near-infrared or mid-wave infrared. Design of spectroscopic components for spectral imaging systems with spectral bands. Background technique [0002] Imaging spectrometer is an organic combination of imaging technology and spectral technology. It can simultaneously obtain two-dimensional spatial information and one-dimensional spectral information of the target to form a data cube, which is widely used in social production, military activities, space and astronomical exploration, and aerospace. remote sensing and many other fields. Its optical system is generally composed of a pre-telescope system and a spectral spectr...

AI Technical Summary

Problems solved by technology

However, compared with convex gratings and concave gratings, the Czerny-Turner structure using planar gratings is limited by aberration correction, and it is difficult to achieve a large relative aperture, and the chromatic distortion and spectral line bending caused by the lengthening of the slit also decrease. Rapid growth, poor aberration correction ability and low resolution

In order to make up for these defects and correct various aberrations, the Czerny-Turner structure based on planar gratings is often used in spectral imaging systems with small aberrations and large F numbers, and in order to increase the freedom of balancing aberrations, each component often has different degrees of Rotation and eccentricity, high requirements for design and assembly, long development cycle

[0005] In addition, other spectrometer splitting systems based on planar gratings generally increase the degree of freedom of the balance system by adding components. The system is relatively complex and requires the introduction of multiple sets of lenses or prisms. The slight inclination and eccentricity of each prism or lens will give The image quality of the system will have a serious impact, which will inevitably lead to difficulties in the installation and testing of the entire system, long development cycle and high development costs.

In addition, the light has to go through multiple refractions and reflections to reach the detector. Each refraction and reflection will bring about the loss of light energy, which will inevitably lead to low utilization of light energy in the system.

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