远红外显微成像光学系统的设计与仿真

Design and Simulation of Far Infrared Microscopic Imaging Optical Systems

为了使远红外探测器获得高信噪比的光电信号,围绕与工作波段在50~70μm、像元数量64×64、像元大小120μm×120μm的制冷型凝视焦平面阵列探测器相匹配的透射式远红外显微成像光学系统的设计与仿真等内容,开展了相关工作。通过对杂散光的分析,预测了冷反射效应所产生的不良影响并且提出了相应的解决方案;仿真模拟结果表明,当光学系统的空间分辨率、数值孔径、焦距、有效放大倍率、中心波长分别为200μm、0.25、14 mm、10、61μm时,系统的调制传递函数值和包围圆能量集中度在特征频率5 lp·mm^(-1)处分别达到0.305和80%,能够得到清晰可辨的物像,符合焦平面阵列探测器的工作要求。

This study focuses on the design and simulation of the transmission far infrared microscopic imaging optical system matched with the cooled staring focal plane array detector that operates in the wavelength range of 50—70μm and contains pixel number 64×64,each pixel is 120μm×120μm in size in order to make the far infrared detector obtain optoelectronic signals with a high signaltonoise ratio.Stray light analysis predicts the negative effect caused by cold reflection,and a solution is proposed to address it.The simulation results show that when the designed optical system’s spatial resolution,numerical aperture,focal length,effective magnification,and central wavelength are 200μm,0.25,14 mm,10,and 61μm,respectively,the modulation transfer function value reaches 0.305 at the characteristic frequency of 5 lp·mm^(−1),and the energy concentration of the surrounding circle of the system exceeds 80%.Meanwhile,the optical system’s produced object picture is easily distinguishable,indicating that it meets the functioning criteria of the focal plane array detector.