NEAR-RESONANT NONLINEAR-OPTICAL PROPERTIES OF PSEUDOISOCYANINE J-AGGREGATES IN LANGMUIR-BLODGETT LAYERS

The nonlinear optical properties of pseudoisocyanine J-aggregates in L angmuir-Blodgett films have been investigated by means of degenerate f our wave mixing (DFWM) process. The conversion efficiency of the DFWM signal and the estimated third order susceptibility were found to be c omparable with those of pseudoisocyanine J-aggregates in solution unde r comparable resonance conditions. The intensity dependence of the con verted (DFWM) signal is interpreted as resulting from different proces ses including saturation, exciton-exciton annihilation and secondary p rocesses of dynamical disorder.