Rugged spinel for imaging applications (Conference Presentation)

Rugged optics and window materials with good visible and IR transmission are needed for several sensing and imaging application. Some of the applications require very thick windows or windows in complex geometries, which impose additional limitations on material selection. Magnesium aluminate spinel (MgAl2O4), or spinel for short, is a rugged window material with excellent transmission in ultraviolet to midwave infrared (0.18 – 5.5 m) wavelengths. Spinel is comparable to sapphire and ALON in its ruggedness while having superior transmission near 5 m in wavelength. With its cubic crystal structure, spinel is isotropic unlike sapphire which is birefringent. We have been developing high optical quality spinel ceramics in different shapes and sizes. Current status of these efforts in making spinel windows in large sizes and conformal shapes for several imaging applications will be discussed.