可见近红外波段碲镉汞材料光学常数测定与宽谱增透设计

将碲镉汞(Hg_(1-x)Cd_xTe)红外焦平面器件衬底去除后,其响应波段可拓展到可见光波段,在高光谱成像应用中可显著减小系统的尺寸和重量,对光电探测系统的小型化和微型化具有重要实用价值.而明确碲镉汞材料在可见近红外波段的光学常数,对碲镉汞器件在这一响应波段的性能研究具有重要意义.分别测量了不同组分碲镉汞材料的椭圆偏振光谱,拟合得到了其在400~1 600 nm波段范围内的光学常数值,并利用反射光谱对获得的光学常数进行了验证.采用这些碲镉汞外延材料光学常数测量值,并选用Zn S和YF3分别作为高低折射率的增透膜材料,针对不同响应波段的背入射可见近红外碲镉汞焦平面器件,设计了不同的宽谱增透膜系,响应波段范围内的平均透过率高于90%.

Determination of optical constants of HgCdTe, and the broadband AR coating design

After removing the Hg1-xCdxTe infrared focal plane device substrate, the response bandwidth can be extended to the visible light band, which can significantly reduce the size and weight of the system in the application of hyperspectral imaging, and miniaturize the photoelectric detection system.Miniaturization has important practical value. The determination of the optical constants of HgCdTe materials in the visible near-infrared region is of great significance for the performance of HgCdTe devices in this response band. The ellipsometric spectra of different compositions of HgCdTe materials were measured and their optical constants in the band from 400 to 1 600 nm were fitted. The obtained optical constants were verified by using the reflectance spectra. Using these measured values, and using ZnS and YF3 as the high and low refractive index anti-reflective coating materials respectively, HgCdTe focal plane devices responding to different widths of back-incident near-infrared light have been designed.Spectroscopic AR coatings have an average transmission rate in the range of the response band of more than 90%.