高分辨率探测器短中波红外滤光片的设计及其光谱特性研究

Design and Spectral Analysis of Short and Medium-Wave Infrared Filter for High Resolution Detectors

  • 摘要: 短中波红外滤光片是航天光学遥感相机上的关键器件之一。高分辨率探测器的光谱响应由滤光片的光谱特性决定,其中短中波红外占有很大比重,传统方式制备的短中波红外滤光片与理论值存在差距,使得短中波红外滤光片发生光谱角漂或温漂等现象,在高分辨率探测器中形成高频和低频光谱混合叠加导致复原光谱失真。本文提出了一种高透过率低漂移高分辨率探测器短中波红外滤光片的设计及研制方法。为了达到短中波红外滤光片特定波长滤光特性的要求(在3.5~4.1 μm波段范围内实现98%以上透过率,在2.4~3.35 μm、4.25~6.4 μm两个波段范围内实现截止),以Si材料为滤光片的基底材料,采用模拟染色体遗传交叉算法以带通滤光高低反射率膜堆结构进行了结构迭代设计,薄膜的高折射率材料采用TiO2,低折射率材料采用SiO2,该结构设计使得膜层数量大为减少,通过温漂测试、角漂测试、光谱特性分析及面形测试,短中波红外滤光片达到了前后双波段截止、高通带透过率的目标。环境测试试验表明,短中波红外滤光片膜层与基底材料匹配性适宜、膜层稳定性较高,适用于空间严酷的温度变化、高能粒子辐照环境。

     

    Abstract: The short- and medium-wave infrared filter is a key device in the aerospace optical remote sensing camera. The spectral response of the high-resolution detector is determined by the spectral characteristics of the short- and medium-wave infrared filter. Owing to the gap between the preparation level and theoretical values, the phenomenon of the spectral angle drift or temperature drift occurs, and the mixed superposition of high- and low-frequency spectra is formed in the high-resolution detector, resulting in restoration spectral distortion. This study introduces a design method for a working band of 3.5 μm to 4.1 μm and the development of a short- and medium-wave infrared filter for a high resolution detector. To realize the characteristics of dual band cut-off color separation on the Si substrate (cut-off band wavelength 2.4 μm to 3.35 μm and 4.25 μm to 6.4 μm; transmittance of over 98% in passband wavelength 3.5 μm to 4.1 μm), the film system structure of the F-P band-pass filter is used as the initial structure, which effectively reduces the number of film layers compared with the conventional design concept. The high refractive material of the film is TiO2 and the low refractive material is SiO2, to achieve dual band cut-off. The short- and medium-wave infrared filter achieves the design goal and has the characteristics of dual band cut-off and high band transmittance. In the environmental test, the short- and medium-wave infrared filter exhibits significant stability, and the matching degree between the films is appropriate. The short- and medium-wave infrared filter can be applied in some extreme cases.

     

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