Abstract

Phase conjugation in photorefractive materials has been shown to be a useful technique for coupling two separate laser input beams(1,2). Recently Eason and Smout(2) have demonstrated that two mutually incoherent beams could be coupled in BaTiO₃. We have extended these studies by carrying out beam coupling experiments in BaTiO₃ designed specifically to examine phase locking and to investigate the mechanisms responsible. Our results indicate that two beams co-pump one another in a manner similar to that of self pumping for a single input beam (3). When co-pumping occurs the relative phases of the two conjugate returns are locked in phase to better than λ/10. In the co-pumping mechanism each input beam forms one of the two counter–propagating pump beams in the self-generated four wave mixing (FWM) regions. In this way each conjugate has a common phase reference (Figure 1).

© 1987 Optical Society of America