HgCdTe红外焦平面阵列像素内灵敏度函数仿真

The simulation of intra-pixel sensitivity for HgCdTe infrared focal plane array

对于Fλ/d<2的欠采样成像红外搜索和追踪系统,点目标能量集中在单像素内。由于焦平面阵列像素内灵敏度(IPS:Intra-PixelSensitivity)存在空间非均匀性,会降低目标的能量和质心测量精度。传统的光点扫描实验测试和数值仿真方法可有效表征和分析IPS,但系统和模型复杂度高、效率低,且实验测试无法分析IPS空间非均匀性与探测器参数的关系。针对上述问题,提出基于蒙特卡洛方法的HgCdTe红外焦平面阵列IPS仿真模型,分析了IPS空间非均匀性的影响因素。结果表明,减小像素中心距或增大吸收层厚度,IPS的空间非均匀性减小;随波长增大,IPS的空间非均匀性增大。该仿真和分析对高能量集中点目标测量精度的提升具有重要参考意义。

For the under-sampled imaging infrared search and tracking system which Fλ/d<2,the energy of point target was concentrated on a single pixel.Due to the spatial non-uniformity of intra-pixel sensitivity(IPS)for focal plane array,the calculation accuracy of energy and centroid for point target would be reduced.Light spot scanning test and numerical simulation could effectively characterize and analyze the IPS,but the system and model were highly complex and time-consuming,moreover,experimental tests couldn’t analyze the relationship between the spatial non-uniformity of the IPS and the parameters of photo-detector.Aimed at the above problem,Monte Carlo methods were used to simulate the IPS of HgCdTe infrared focal plane array,and the influencing factors of its spatial non-uniformity were analyzed.The results showed that the spatial non-uniformity of IPS can be reduced by reducing the pixel pitch or increasing the thickness of absorber.With the increase in wavelength,the spatial non-uniformity of IPS increased slightly.The results of simulation and analysis are of great significance for improving the measurement accuracy of high energy concentration point target.