Enhancement of backward third-harmonic generation in a one-dimensional PIM/NIM periodic structure

Abstract

A numerical simulation is reported for backward third-harmonic generation (BTHG) in a one-dimensional periodic structure containing a stack composed of positive-index material (PIM) and negative-index material (NIM). A multiple-scale method is used to formulate a completed set of coupled-mode equations with inhomogeneous higher-order nonlinear terms for both electric and magnetic fields. The coupled equations are numerically solved to simulate output third-harmonic frequency pulses and their conversion efficiencies by a fast Fourier transform–pulse propagation method. Finally, the numerical results validate the idea that using a combination of the negative-index phase-matched condition, which is created by engineering the dispersive property of the NIM layer, and local field enhancement, which is created by arranging PIM and NIM layers in an optimal periodic fashion, yields a dramatic enhancement of BTHG conversion efficiency. © 2018 Optical Society of America.