Degenerate four-wave mixing in solutions of pure and iodine-doped polyphenylacetylene

Abstract

The third-order nonlinear optical susceptibility x (3) is measured in solutions of undoped and iodine-doped polyphenylacetylene by nanosecond degenerate four-wave mixing (DFWM). Phase conjugation in iodine-doped polyphenylacetylene is reported here for the first time. Polyphenylacetylene used in this work is polymerised with a group VI metal carbonyl as catalyst. Phase conjugate reflectivity is measured as a function of incident laser power, concentration and doping levels of iodine. Both undoped and iodine-doped polyphenylacetylene give good phase conjugate signals, with enhanced reflectivity in doped samples, at modest Q-switched laser power levels. x (3) for PPA in solution is found to be 1.1 x 10 -20 m 2/V 2 and doping (22%) with iodine enhances it to 2 x 10 - 18 m 2/V 2.