A single photonic cavity with two independent physical synthetic dimensions

TL;DR

This paper demonstrates a novel approach to simulate higher-dimensional physics using a single photonic ring resonator endowed with two independent synthetic dimensions, revealing complex phenomena like spin-orbit coupling and topological phase transitions.

Contribution

The study introduces a system with two independent synthetic dimensions in a single ring resonator, enabling exploration of complex higher-dimensional physics in a simple photonic setup.

Findings

Observation of effective spin-orbit coupling

Detection of a Meissner-to-vortex phase transition

Realization of chiral currents in synthetic dimensions

Abstract

The concept of synthetic dimensions, which has enabled the study of higher-dimensional physics on lower-dimensional physical structures, has generated significant recent interest in many branches of science ranging from ultracold-atomic physics to photonics, since such a concept provides a versatile platform for realizing effective gauge potentials and novel topological physics. Previous experiments demonstrating this concept have augmented the real-space dimensionality by one additional physical synthetic dimension. Here we endow a single ring resonator with two independent physical synthetic dimensions. Our system consists of a temporally modulated ring resonator with spatial coupling between the clockwise and counterclockwise modes, creating a synthetic Hall ladder along the frequency and pseudospin degrees of freedom for photons propagating in the ring. We experimentally observe a wide variety of rich physics, including effective spin-orbit coupling, magnetic fields, spin-momentum locking, a Meissner-to-vortex phase transition, and chiral currents, completely in synthetic dimensions. Our experiments demonstrate that higher-dimensional physics can be studied in simple systems by leveraging the concept of multiple simultaneous synthetic dimensions.