Optical Design Study in the 1-5μm Spectral Band with Gradient-Index Materials

A design study is conducted in the 1-5 mu m wavelength band for an F/3, 15 degree full field of view, 38mm focal length imaging system. A survey of preferred materials shows the chromatic properties of homogeneous materials in different regions of this spectrum. A survey of GRIN materials, including zinc selenide zinc sulfide GRIN, aluminum oxynitride GRIN, and chalcogenide GRIN, expands the available chromatic properties in this spectral band. Baseline homogeneous triplet designs are explored and compared to previous studies in the literature. The inclusion of a GRIN material in the three element design improves the chromatic correction and results in a system that is nearly diffraction-limited. The three element design is reduced to two elements, where both elements are GRIN, while maintaining comparable performance to the homogeneous triplet.