LOCALIZED-DELOCALIZED TRANSITION OF THE EXCITON AND SCALING DESCRIPTION OF PHASE-CONJUGATED WAVE GENERATION

Under nearly resonant pumping of Frenkel excitons, the third-order optical process generating phase-conjugated waves is theoretically investigated by taking full account of the effect due to static on-site disorder and finite same size. The scaling theory of the Anderson localization allows us to show that the phase-conjugated signal has the spectral anomaly for pump and probe frequencies around the exciton mobility edge. We systematically evaluate the dependence of the phase-conjugated signal on various physical quantities, namely, randomness, the detuning of the pump and probe frequencies from the exciton mobility edge, the misalignment of two pump beams, and the system size.