基于单次曝光多光谱关联成像系统带通滤波器的研究

多光谱关联成像与传统点到点的成像方式不同，该技术是采用调制、解调的方式获取目标的图像信息。搭建了一套基于固定相位板的单次曝光多光谱关联成像系统，完成了多光谱关联成像系统中薄膜器件的研制。选择BK7玻璃作为基底材料，氧化铌(Nb₂O₅)和二氧化硅(SiO₂)为高、低折射率材料。根据光学薄膜基础理论，结合膜系设计软件进行膜系设计和模拟分析，通过建立膜系优化评价函数，实现了0°~30°入射450~700 nm带通滤光膜的设计，并在OZZSQ900型箱式真空镀膜机上完成了该薄膜的研制。通过优化SiO₂膜沉积速率，改善了薄膜表面缺陷，降低了散射损耗。对膜层的残余蒸镀进行分析，利用最小二乘法建立膜层厚度与残余蒸镀量之间拟合函数，调整监控方式，减小残余蒸镀，提高了制备过程中膜厚控制精度。采用安捷伦Cary5000分光光度计测试，在350~440 nm和710~800 nm波段透过率 T ＜0.5%，450~700 nm范围内，光线入射角0°~30°时平均透过率 T >98%的带通滤波器，满足系统使用要求，该研究具有重要的实际意义和工程价值。

Research on the bandpass filter used for single-exposure multi-spectral ghost imaging system

Different from the traditional point-to-point imaging, multi-spectral ghost imaging retrieve the image information of the target by means of modulation and demodulation. In this paper, a single-exposure multi-spectral ghost imaging system based on a fixed phase modulator was built, and the development of thin-film devices in the system was completed. In the thin film, BK7 glass was chosen as the substrate, niobium oxide (Nb₂O₅) and silicon dioxide (SiO₂) were used as the high and low refractive index materials, respectively. Based on the basic theory of optical thin film, the simulation analysis and the film system design were carried out by the film system design software, through setting up evaluation function for film optimization, the design of 450-700 nm band-pass film filter with an incidence angle of 0°-30° was realized and the research and development of this film was completed on OZZSQ900 box-type vacuum coating machine. Through optimizing deposition rate of SiO₂ film, the surface defects and scattering loss of film were reduced. The residual evaporation deposition of film was analyzed, the fitting function between film thickness and residual evaporation deposition by least square method was established, monitoring ways was adjusted, residual evaporation deposition was reduced and the accuracy of film thickness control during preparation process was improved. From the test performed by Agilent Cary5000 spectrophotometer, the transmittance is less than 0.5% in the bands of 350-440 nm and 710-800 nm, and higher than 98% in the range of 450-700 nm at the incident angle of 0°-30°, which meets the requirements of the imaging system. The study has important practical significance and engineering value.