渐晕对红外光学系统光谱透过率测量的影响

Influence of aperture position and size on infrared lens spectral transmittance measurements

摘要: 在基于回返法的红外光学系统光谱透过率测试系统中，光阑等元件的位置在测量时会对红外镜头测量光谱透过率造成影响。针对这一问题，通过建立渐晕模型，对测试系统的测量段光束的渐晕进行了分析，推导出光阑等元件放置在不同位置处产生的渐晕公式。实验结果表明，保持空测和实测的相对渐晕一致，可以有效减小渐晕变化对红外镜头透过率测量的影响。

Abstract: In the infrared spectroscopic transmittance testing apparatus based on the retro-reflective method, the position and size of the aperture will affect the measurement of the spectral transmittance of the infrared lens during measurement. To address this issue, a vignetting model was established to analyze the vignetting of the measurement beam in the testing apparatus. The vignetting formula generated by placing apertures and other components at different positions was derived. Experimental results demonstrate that maintaining consistency in relative vignetting between the empty and actual measurements effectively reduces the impact of vignetting variations on the measurement of spectral transmittance of the infrared lens.