Diffractively Corrected Risley Prim For Infrared Imaigng

摘要

This paper presents experimetnal results using a ZnSe Risley prism scanner in which diffractive gratings were etched into the prism faces to correct for chromatic aberrations. Risley prism scanners, which consist of independently rotating prisms, offer distinct advantages over mirrored systems. The faces of the two scanner elements are parallel and adjacenet to one another, resulting in a simple, lightweight, and compact system with extremely high pointing stability and accuracy. Laboratory rwesults for the scanner, when used in a midwave infrared (MWIR) imaging system, demonstrated a total field of view +-22.5 degrees with almost no aberrations. The optical performance of the scanner demonstrated a factor of two improvement in resolution when compared to an equivalent scanner using no diffractive correction. We conclude that the use of diffractively corrected prisms offer a new potential for using Risley prisms as a alternative lightweight scanner in missile seekers.