Spatial light modulation using two-wave mixing properties of photorefractive materials

Abstract

A design is presented which combines concepts of 2-D spatial light modulation with photorefractive coupling for a subsystem applicable to optical communications. Laser diodes are the transmitters of choice in laser spacecraft communications. However, the outputs from these devices are not directly usable in that massive bulky conventional optics are required to correct and direct a given beam. Furthermore, beam characteristics change with time and in some applications, due to channel effects, affecting SNRs and overall system efficiencies. Hence a means to not only replace heavy bulky optics with lightweight optical elements but to modify these optics in situ in real time is highly desirable.