变间隙法布里-珀罗(F-P)干涉腔反射率确定方法

变间隙法布里-珀罗(F-P)干涉光谱成像系统获取的干涉条纹承载着目标重要的干涉信息，其正弦性的好坏和调制度的高低直接影响了目标干涉信息的提取。而变间隙法布里-珀罗(F-P)干涉腔材料的反射率值是变间隙F-P干涉光谱成像系统的重要性能参数。为提高变间隙F-P干涉光谱成像系统整个系统的性能，从系统干涉条纹的正弦性和调制度两方面约束了变间隙F-P干涉腔反射率值的选取。文中分别建立了干涉条纹正弦性和调制度与变间隙F-P干涉腔材料反射率之间的数学关系，并给出合理地目标函数，以确保干涉条纹正弦性和调制度同时达到相对最佳值时，变间隙F-P干涉腔材料的反射率最佳。此外，搭建了长波红外变间隙F-P干涉式光谱成像系统，采用测量聚丙烯薄膜的光谱透过率实验验证了上述理论分析的正确性。

A method to determine reflectivity of F-P interferometic cavity with variable gap

There is many interference information of targets contained in the interference fringes which are obtained by the variable gap Fabry-Perot (F-P) interferometric imaging system. The sinusoidal nature and modulation of the interference fringes directly affect the extraction of interference information of the target. The reflectivity value of the variable gap Fabry-Perot (F-P) interference cavity material is an important performance parameter of the variable gap F-P interferometric imaging system. In order to improve the performance of the variable gap F-P interferometric imaging system, the reflectivity of the variable gap F-P interferometric cavity depends on the sinusoidal nature and the modulation of the interference fringes. In this paper, the mathematical relationship between the sinusoidal nature and modulation of interference fringes and the reflectivity of F-P cavity with variable gap was established respectively and a reasonable objective function was given. When the sinusoidal nature and modulation of the interference fringes were relatively optimal at the same time, the optimal reflectivity of material of the F-P cavity with variable gap was found. The long wave infrared variable gap F-P interference spectral imaging system was built, and the correctness of the above theoretical analysis was verified by measuring the spectral transmittance of polypropylene film.