Tailoring Topological Edge States with Photonic Crystal Nanobeam Cavities

TL;DR

This paper introduces a flexible photonic topological insulator design using SSH photonic crystal nanobeam cavities, enabling tailored topological edge states through two-dimensional mode coupling control.

Contribution

It presents a novel nanobeam cavity approach that allows two-dimensional manipulation of topological edge states, expanding the design possibilities for topological photonic devices.

Findings

Selective tailoring of single or double TESs in the telecommunication band.

Enhanced control over mode coupling in two dimensions.

Deeper understanding of SSH model applications in photonics.

Abstract

The realization of topological edge states (TESs) in photonic systems has provided unprecedented opportunities for manipulating light in novel manners. The Su-Schrieffer-Heeger (SSH) model has recently gained significant attention and has been exploited in a wide range of photonic platforms to create TESs. We develop a photonic topological insulator strategy based on SSH photonic crystal nanobeam cavities. In contrast to the conventional photonic SSH schemes which are based on alternately tuned coupling strength in one-dimensional lattice, our proposal provides higher flexibility and allows tailoring TESs by manipulating mode coupling in a two-dimensional manner. We reveal that the proposed hole-array based nanobeams in a dielectric membrane can selectively tailor single or double TESs in the telecommunication region by controlling the coupling strength of the adjacent SSH nanobeams in both vertical and horizontal directions. Our finding provides an in-depth understanding of the SSH model, and allows an additional degree of freedom in exploiting the SSH model for integrated topological photonic devices with unique properties and functionalities.