Resonant Combinatorial Frequency Generation Induced by a <italic>PT</italic>-Symmetric Periodic Layered Stack

Abstract

The nonlinear interaction of waves in PT-symmetric periodic stacks with an embedded nonlinear anisotropic dielectric layer illuminated by plane waves of two tones is examined. The three-wave interaction technique is applied to study the nonlinear processes. It is shown that the intensity of the three-wave mixing process can be significantly enhanced in resonant cavities based on PT-symmetric periodic structures, especially as the pumping wave frequency is near the coherent perfect absorber-lasing resonances. The main mechanisms and properties of the combinatorial frequency generation and emission from the stacks are illustrated by the simulation results and the effect of the layer arrangement in PT-symmetric walls of resonator on the stack nonlinear response is discussed. The enhanced efficiency of the frequency conversion at Wolf-Bragg resonances is demonstrated. It has been shown that Wolf-Bragg resonances of very high orders may lead to the global maxima and nulls of the scattered field. The analysis of the effect of losses in nonlinear dielectric layer on the combinatorial frequency generation efficiency has shown that the rate of losses may amplify the intensity of the frequency mixing process.