Design of athermal and bifocal infrared lens for space camera

A new kind of optical lens with light weight, compact structure, good image quality, all-weather work, scurviness environment is designed based on the triturating requirement of the space camera for debris. The lens breaks through the flaw that the conventional system always has complex structure, heavy weight, large volume, and only one focal.Diffractive optical element is used to calibrate the chromatic aberration and temperature difference by its characteristics. Ge and Si are utilized to calibrate the spherochromatic aberration. The result indicates that when spatial frequency is 16 lp/mm, the MTFs are above 0.45 and 0.55 in short focal and long focal, respectively. The MTF is approaching to the diffraction limit. The maximal RMS diameters of spot diagram are 15.8 μm and 7.2 μm in short focal and long focal, respectively, which are less than the diameter of detecting sensor. It shows that the image quality of the lens is very good, and it calibrates the temperature difference in real circumstance of the application.