Long focal length large aperture optical passive athermalization MWIR optical system

In this research, we designed an MWIR optical system, which is equipped with long focal length, large aperture, optically athermalization. The optical system has been athermalized under wide temperature range (-40 to 70 DEG C) by means of optically passive compensation of more two-optical-material and one housing material combination. The optical system only is composed of six lenses, the transmission of the optical system is high. The final optical system has a 1200mm focal length and a 0.46 degrees x 0.37 degrees field of view. The modulation transfer function of the optical system is close to the diffraction-limit, the 4-bar target image of the MWIR imager is very legible. The design and test results show that the image quality of the optical system is perfect, and it can meet the requirements of the high definition and high performance MWIR imager and needn't focus from minus 40 degrees centigrade to positive 70 degrees centigrade.