Abstract

The utilization of lasers for precision-guidance applications has stimulated much interest in novel photodetection devices capable of operating in conjunction with short-duration pulses typical of Q-switched YAG designators. Position-sensitive photodetectors (PSPDs), in particular, offer unique advantages in providing the capability of tracking laser-designated targets without requiring gimballing mechanisms. They exploit the lateral photoeffect to deliver electrical signals, which can be processed to extract both horizontal and vertical components of the seeker-to-target look angle.¹ The lateral photocurrents, which result from the nonuniform illumination of the detector when operated in a photovoltaic mode, are collected at four electrodes suitably located at the edge of the active area. After amplification and ratiometric amplitude processing, these signals provide two de analog outputs which are linearly related to the spot position and, thus, can be exploited for tracking the target over the total field of view of the seeker.²

© 1976 Optical Society of America