基于单频激光干涉的凸面光栅成像光谱仪球面精确同心装调方法及其算法研究

On the research of hyperspectral remote sensing in geological survey, mineral mapping, environmental monitoring, imaging spectrometers with convex grating have the advantages of high SNR, high resolution, compact and so on. Imaging spectrometers with convex grating represent one of the development of advanced remote sensing instruments. All of the spherical optics have a common center, this is the key for instrument to achieve no astigmatism, distortion-free and compact. However, conventional concentric alignment method by visual tracking laser spot is low precision, no quantization, random. It is difficult to meet the requirements of high concentricity for instrument. Currently, only NASA has developed precise concentric alignment method, but fewer is reported. Breaking out the traditional thought that single-frequency laser interferometry is used in optical testing. This project presents a spherical concentric interferometry alignment method. By bringing single-frequency laser interferometry to concentric spherical alignment, organic integration will be carried out between single-frequency interference testing theory and convex grating concentric characteristics based on studying the geometric characteristics of each optical aberration in concentric system. The numerical model of the relationship between interference fringe parameters and aberration coefficients will be set up. The influence of concentric interference alignment accuracy and the influence of concentricity error parameters for each component on spectral properties of the instrument will be calculated. Concentricity error compensation algorithm will be given by spectral properties of the instrument to optimize the structure parameters. The numerical model of concentric interference alignment method will be amended and perfected by experiment. The ultimate realization of convex grating imaging spectrometer concentric error is less than 10nm. In this way, the problem of spherical concentric alignment is solved.

在地质勘探、矿物填图、环境监测等高光谱遥感研究中，凸面光栅成像光谱仪集高信噪比、高分辨率、小型化等优势于一体，代表了先进地学仪器的发展方向之一。所有光学球面具有公共球心是仪器零象散、零畸变、小型化的关键。但是常规目测追踪激光点斑的同心装调方法精度低、无量化、随机性大，难以满足仪器高同心度的要求。目前仅美国NASA研究出精确同心装调的方法，而公开报道较少。本项目突破单频激光干涉用于光学检测的传统思想，研究球面同心干涉装调方法。将单频激光干涉理论与凸面光栅同心特性有机结合，在研究同心系统各光学像差几何特征基础上，建立干涉条纹特性参数与像差系数关系模型；研究同心干涉方法精度及各元件同心误差参数对仪器光谱性能的影响；基于仪器光谱性能参数建立同心误差补偿算法，对系统结构参数进行优化；并通过实验对同心干涉装调解析模型进行校正和完善。最终实现凸面光栅成像光谱仪同心误差小于10nm，解决精确同心装调问题。

本项目研究的基于单频激光干涉的凸面光栅成像光谱仪球面同心装调方法，因根据单频激光双光束干涉条纹的离焦量计算各球心之间的距离，故有了在同心方法中对各个球心之间的距离进行实时精确反演计算和修正的方法，从而实现了凸面光栅成像光谱仪各球面的高精度同心，还能对同心误差进行量化分析。另外，采用单频激光干涉测试方法进行精确同心降低了同心的随机性，总体上会降低同心装调方法中的人为因素影响，缩短装调周期，显著提高凸面光栅成像光谱仪装调的效率，使同心方法及实现过程科学化、系统化、规范化。本项目实现了凸面光栅成像光谱仪同心精度及误差的量化分析，其同心装调精度可达到几纳米甚至更高，实现凸面光栅成像光谱仪科学、规范、高精度的同心装调，加快凸面光栅成像光谱仪的研究步伐，推进我国新型高性能遥感地质设备的发展，使我国遥感地质各相关领域研究能力跻身世界先进行列。