光学窗口与薄膜材料的红外热光系数研究

With the application development of infrared imaging system in high speed and super hypersonic speed, the optical window and thin films face the challenge of high temperature and thermal shock due to the aerodynamic heating effect. Therefore, the thermal radiation of optical window and thin films have become main obstacles to improve target detection ability of infrared imaging system. The continuous thermal radiation of optical window and films are determined by their infrared thermo optic coefficient which should be obtained by measuring the continuous temperature variation of dielectric constants. Current related studies on infrared thermo optic coefficient (from normal atmospheric temperature to 600℃) of optical window and thin films are very rare, so these studies have great significance for scientific research and applications. This research will focus mainly on the application of typical optical window (zinc sulfide, germanium, silicon, sapphire, zinc selenide, spinel, fused silica, crystalline quartz) and thin film materials (ZnS, Ge, Si, SiO2, Al2O3, YF3, Y2O3). Make a break through in the correction of infrared dielectric constants’ dispersion model, the measurement of high temperature infrared elliptic polarization parameters and transmission spectra, and the inversion calculation software programming of high temperature infrared dielectric constant. Furthermore, this research will study the infrared thermo optic coefficient of typical optical window and thin film materials and provide basic technical support for the evaluation and control of the thermal radiation of optical window and thin films at high temperature.

随着红外成像探测系统在高声速和超高声速平台上应用的发展，气动加热效应使光学窗口与薄膜面临着高温和热冲击的挑战，光学窗口与薄膜的热辐射成为提高红外成像探测系统目标探测能力的主要障碍。光学窗口与薄膜的连续热辐射效应取决于其红外热光系数，而热光系数则必须通过测量介电常数的连续温度变化获得。目前光学窗口与薄膜的红外热光系数（常温到600℃）的相关研究鲜见报道，因此红外热光系数的研究具有重要的科学意义和应用价值。本项目重点针对典型光学窗口（硫化锌、锗、硅、蓝宝石、硒化锌、尖晶石、熔融石英、晶体石英）和薄膜材料（ZnS、Ge、Si、SiO2、Al2O3、YF3、Y2O3）的应用，突破红外介电常数色散物理模型的修正、高温红外椭圆偏振参数和透过率光谱的测试、高温红外介电常数反演计算软件编制，研究典型光学窗口与薄膜材料的红外热光系数，为高温下光学窗口与薄膜热辐射的评价与控制提供关键基础技术支撑。

随着红外成像探测系统在高声速和超高声速平台上应用的发展，气动加热效应使光学窗口与薄膜面临着高温和热冲击的挑战，光学窗口与薄膜的热辐射成为提高红外成像探测系统目标探测能力的主要障碍。光学窗口与薄膜的连续热辐射取决于其红外热光系数，而热光系数则必须通过高温光谱性能的测试得到。该项目针对光学窗口与薄膜材料的红外热光系数开展研究工作，完成了以下研究：（1）采用研制的专用测试附件实现了光学窗口与薄膜室温至600℃温度范围内的红外透射光谱性能测试，并进行了测试精度评价；（2）测试得到了常用光学窗口和薄膜的高温透射光谱性能，初步建立了光学窗口和薄膜材料的高温光谱性能数据库；（3）采用解析计算和光谱拟合结合的方法，计算得到了常用光学窗口材料的红外热光系数，并在得到光学窗口材料红外热光系数的基础上采用光谱拟合的方法计算得到了常用薄膜材料的热光系数，进而建立了光学窗口与薄膜材料红外热光系数数据库；（4）建立了光学多层膜高温热辐射与光学窗口与薄膜热光系数的关系，实现了多层光学薄膜高温热辐射的间接表征，并与直接测量结果进行了比对，并进行了精度分析。该项目的研究，国内首次实现了光学窗口与薄膜室温600℃大温度范围的红外透射光谱测试，并反演计算得到了常用光学窗口与薄膜材料的红外热光系数，实现了光学多层膜高温热辐射的间接表征，具有重要的科学意义和很强的应用背景。