Effects of Grating Erasure on Beam Fanning and Self-Pumped Phase Conjugation

The photorefractive phenomena of beam fanning and phase conjugation have been used to demonstrate such operations as optical limiting, interconnecting, tracking, and a wide variety of applications utilizing phase conjugate mirrors. Many other applications can be realized when two laser beams interact in a photorefractive crystal since one of the beams can be used to control the other. For example, it is possible to amplify, deplete, direct, switch, or modulate one of the beams with the other. The photorefractive effect provides the underlying mechanism for these demonstrations of all-optical light by light control. These applications depend upon the formation of particular photorefractive gratings and the perturbation of those gratings. Only recently has attention been given to the importance of the physical location of the gratings within the crystal.1,2,3