Giant Enhancement of Nonlinear Harmonic Generation in a Silicon Topological Photonic Crystal Nanocavity Chain

TL;DR

This paper demonstrates a significant enhancement of third-harmonic generation in a silicon topological photonic crystal nanocavity chain, leveraging topological edge modes for robust, high-efficiency nonlinear optical processes on-chip.

Contribution

It introduces a topological nanocavity chain design that dramatically boosts nonlinear harmonic generation through edge mode localization, surpassing trivial structures.

Findings

Three orders of magnitude THG enhancement in topological chain

Edge mode robustness extends beyond individual nanocavities

Potential for on-chip topology-driven nonlinear photonics

Abstract

Strongly enhanced third-harmonic generation (THG) by the topological localization of an edge mode in a Su-Schrieffer-Heeger (SSH) chain of silicon photonic crystal nanocavities is demonstrated. The edge mode of the nanocavity chain not only naturally inherits resonant properties of the single nanocavity, but also exhibits the topological feature with mode robustness extending well beyond individual nanocavity. By engineering the SSH nanocavities with alternating strong and weak coupling strengths on a silicon slab, we observe the edge mode formation that entails a THG signal with three orders of magnitude enhancement compared with that in a trivial SSH structure. Our results indicate that the photonic crystal nanocavity chain could provide a promising on-chip platform for topology-driven nonlinear photonics.