Generalized Laws of Refraction and Reflection at Interfaces between Different Photonic Artificial Gauge Fields

TL;DR

This paper formulates and experimentally demonstrates generalized laws of refraction and reflection at interfaces between regions with different artificial gauge fields, enabling new control over wave propagation in photonic systems.

Contribution

It introduces the generalized Snell law for gauge interfaces, demonstrates experimental validation, and proposes a gauge imaging system for wavepacket shape reconstruction.

Findings

Derived the generalized Snell law for gauge interfaces

Experimentally validated total internal reflection and transmission

Proposed a gauge imaging system for wavepacket reconstruction

Abstract

Artificial gauge fields enable extending the control over dynamics of uncharged particles, by engineering the potential landscape such that the particles behave as if effective external fields are acting on them. Recent years have witnessed a growing interest in artificial gauge fields that are generated either by geometry or by time-dependent modulation, as they have been the enablers for topological phenomena and synthetic dimensions in many physical settings, e.g., photonics, cold atoms and acoustic waves. Here, we formulate and experimentally demonstrate the generalized laws of refraction and reflection from an interface between two regions with different artificial gauge fields. We use the symmetries in the system to obtain the generalized Snell law for such a gauge interface, and solve for reflection and transmission. We identify total internal reflection (TIR) and complete transmission, and demonstrate the concept in experiments. Additionally, we calculate the artificial magnetic flux at the interface of two regions with different artificial gauge, and present a method to concatenate several gauge interfaces. As an example, we propose a scheme to make a gauge imaging system - a device that is able to reconstruct (image) the shape of an arbitrary wavepacket launched at a certain position to a predesigned location.