Tunable Antichiral Hinge State in Photonic Synthetic Dimensions

TL;DR

This paper introduces a method to realize and control tunable antichiral hinge states in 3D topological photonic systems using synthetic dimensions and electro-optic modulation, enabling programmable topological transport.

Contribution

It proposes a novel scheme for creating and tuning antichiral hinge states in 3D topological insulators using photonic synthetic dimensions and electro-optic modulators, simplifying experimental implementation.

Findings

Demonstrated tunable antichiral hinge states via photonic transmission spectra.

Designed experimental schemes with electro-optic modulators to control hinge state properties.

Confirmed robustness and programmability of topological transport in the proposed system.

Abstract

Recent research in 2-dimensional (2D) topological matter has generalized the notion of edge states from chiral to antichiral configurations with the same propagating direction at parallel edges, revealing a rich variety of robust transport phenomena. Here, we propose that antichiral hinge states can emerge in a 3D higher-order topological insulator/semimetal, where two surface/bulk Dirac points are connected by the hinge states. The band dispersion can be controlled and tilted independently for each hinge using properly designed tunnelings, resulting in tunable antichiral hinge states with programmable propagation direction and velocity. Moreover, we propose experimental realization schemes based on a 1D coupled cavity array with additional synthetic dimensions represented by the photonic orbital angular momentum and frequency. We innovatively introduce both longitudinal and transversal electro-optic modulators to generate the desired tunable tunnelings along the synthetic dimensions, which significantly reduce the experimental complexity by eliminating the need for beam splittings and auxiliary cavities. The tunable antichiral hinge states are confirmed by the photonic transmission spectra. Our work presents the robust and tunable antichiral hinge-state transports which paves the way for exploring novel topological matter and their device applications.