Passive athermalization of MWIR optical designs utilizing different infrared optical materials

In this paper, different optical designs, which are composed of different MWIR optical materials, are utilized for passive athermalization and their performance in athermalization are analyzed. The optical designs are carried out by preserving the athermal property as well as keeping the image quality at higher levels within the working temperature between –40 ºC and +60 ºC. The passive athermalization process begins with the calculation of athermalization conditions of candidate material properties. By considering these conditions, athermal material pairs are chosen. To reduce optical aberrations, aspherical surfaces are utilized during the optimization process. At the end of the design phase, the performance of different configurations of athermal optical material pairs, which are enclosed by aluminum alloy housing material, are presented.