静态干涉系统具有稳定性好、 抗干扰能力强的优势, 但其缺点是光谱分辨率低并且光谱测试范围不易调整。 针对静态干涉型成像光谱系统光谱分辨率低且不可调等问题, 设计了一种新型静态成像光谱系统。 系统由光束整形模块、 新型静态干涉调制模块以及成像模块构成。 光束整形模块将入射光缩束并整形为平行光, 进而保证入射干涉具后可以获得较好的干涉效果; 新型静态干涉调制模块对入射光进行相干处理。 在双折射干涉结构的基础上进行了改进, 在不改变原有静态干涉具尺寸的基础上提高了系统的光谱分辨率, 并实现了光谱分辨率的静态调制; 成像模块完成对目标区域二维可见光图像的采集。 系统核心部件由两组光轴相互正交的Wollaston棱镜作为分光器件, 在两棱镜间放置电光调制模块, 实现光程的静态扫描。 分析了新型静态成像光谱系统的工作原理, 给出了入射角、 折射角等主要参数的函数表达式, 并构建了系统的数据模型。 通过绘制系统光线追迹图的方式, 得到了该系统横向剪切量的函数方程, 并对影响横向剪切量的各个参数进行了分析与讨论。 通过仿真计算了改变结构角、 晶体厚度以及调制度等参数对横向剪切量的影响程度, 并定量计算了两个参数对系统光谱分辨率的影响程度。 由仿真分析结果可知, 增大结构角与加宽调制晶体厚度都可以为系统提供更大的光程差。 故通过电光调制的方式实现横向剪切量的静态扫描是可行的, 可以实现静态光谱图像的获取。 在实验中对660 nm激光进行了测试。 新型静态干涉模块采用孔径20 mm×20 mm, 厚度10 mm的两块光轴相反的Wollaston棱镜与厚度10 mm的电光调制晶体构成。 当调制度分别是0.000 2和0.000 6时, 成像模块采集得到干涉条纹具有明显差异。 当调制度增大时, 其干涉条纹密度增大, 说明采用越大的调制度, 系统对应的光谱静态扫描能力越强, 对光谱分辨率的控制越好。 由此可见, 本静态成像光谱系统在控制电光晶体调制度的条件下具有光谱分辨率可调的特性, 验证了系统的可行性。

The static interference system has the advantages of good stability and strong anti-interference ability, as well as disadvantages of low spectral resolution, nonadjustable spectral resolution, and so on. Aiming at such shortcomings of static interferometric imaging spectroscopy systems, a novel static imaging spectroscopy system is designed in this paper. The system consists of a beam shaping module, a novel static interference modulation module and an imaging module. The beam shaping module is used to shrink and shape the incident light into parallel light, so as to ensure a better interference effect. In addition, the novel static interference modulation module is used to coherently process incident light. The birefringence interference structure is modified in the system. On the basis of unchanged size of the original static interference, the spectral resolution of the system is improved, and the static modulation of the spectral resolution is realized. The imaging module is used to acquire two-dimensional visible images of the target area. The core components of the system consist of two sets of Wollaston prisms, as a spectral device, whose optical axes are orthogonal to each other. The electro-optical modulation module is placed between the two prisms for static scanning of the optical path. Besides, the working principle of the new static imaging spectroscopy system is introduced, and the system data model is given. The function expressions of the main parameters such as angle of incidence and angle of refraction are given, and the system data model is constructed. By plotting ray tracing graphs of the system, the functional equations of the lateral shear of the system are obtained, and the parameters that affect the lateral shear are analyzed and discussed respectively. The extent to which the parameter’s changes of structural angle, crystal thickness and modulation degree affect lateral shear is calculated by simulation. And the extent to which the parameter’s changes of structural angle, crystal thickness affect the spectral resolution is calculated quantitatively. Accordingly, a larger optical path difference can be achieved by appropriately increasing the structural angle and the crystal thickness. Therefore, it is feasible to realize the static scanning of lateral shear by means of electro-optic modulation, by which the acquisition of static spectral images can be achieved. In the experiment, 660 nm laser is tested. Two Wollaston prisms with opposite optical axes (Aperture: 20 mm×20 mm, thickness: 10 mm) and electro-optic modulated crystals (Thickness: 10 mm) are used in the novel static interference module. When modulation degree is 0.000 2 and 0.000 6 respectively, there are obvious differences in the interference fringes obtained by the imaging module. That the density of the interference fringe increases with the increase of modulation degree shows that the greater the modulation degree is, the stronger the spectral static scanning ability is, the more easily the spectral resolution is controlled. Thus, the static imaging spectroscopy system is characterized by adjustable spectral resolution under the condition of controlling the electro-optic crystal modulation degree. The feasibility of the system is verified.