Reducing the risk of laser damage in a focal plane array using linear pupil-plane phase elements.

A compact imaging system with reduced risk of damage owing to intense laser radiation is presented. We find that a pupil phase element may reduce the peak image plane irradiance from an undesirable laser source by two orders of magnitude, thereby protecting the detector from damage. The desired scene is reconstructed in postprocessing. The general image quality equation (GIQE) [Appl. Opt.36, 8322 (1997)] is used to estimate the interpretability of the resulting images. A localized loss of information caused by laser light is also described. This system may be advantageous over other radiation protection approaches because accurate pointing and nonlinear materials are not required.