Optical phase conjugation by non-resonant degeneration four-wave mixing in volume media of DR1-doped PMMA

Optical phase conjugation (PC) by non-resonant degenerate four-wave mixing (DFWM) in thick media of poly(methyl methacrylate) (PMMA) with doped disperse red 1 (DR1) 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 more than 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 modulation of ordering of the DR1 chromophore is the main mechanism of the PC wave generation. Other mechanisms involved in the configuration of all vertical polarization waves are also examined. Influence of the squeezing process in making volume samples on the PC wave efficiency is significant.