High-efficiency optical phase conjugation by degenerate four-wave mixing in volume media of disperse red 1-doped poly(methyl methacrylate)

High-efficiency optical phase conjugation (PC) by degenerate four-wave mixing in stress-processed volume media of disperse red 1 (DR1)-doped poly(methyl methacrylate) in the transparent region (647 nm) is reported. With vertically polarized counterpropagating pump waves, PC reflectivities of 43% and 37% were achieved, respectively, for a horizontally and vertically polarized probe wave, which is 50 times higher than the value reported on resonance. Reflectivities over 30% were achieved over a wide range of intensity for both polarization configurations. Photoinduced reorientation of the DR1 chromophore through trans-cis-trans isomerization is the dominant mechanism for the PC wave generation. Other mechanisms involved in the configuration of all vertical polarization waves are also examined. The roles of the polymer matrix and azo-dye photoisomerization in this high-efficiency PC process are also discussed. (C) 2002 American Institute of Physics.