Experimental Observation of Large Chern numbers in Photonic Crystals

TL;DR

This study experimentally demonstrates large Chern numbers (2, 3, 4) in ferrimagnetic photonic crystals through microwave transmission, confirming theoretical predictions and advancing topological photonics research.

Contribution

It provides the first experimental observation of large Chern numbers in photonic crystals, expanding the understanding of topological phases in bosonic systems.

Findings

Large Chern numbers observed (2, 3, 4)

Excellent agreement between experiment and theory

Edge mode dispersion matches Chern number calculations

Abstract

Despite great interest in the quantum anomalous Hall phase and its analogs, all experimental studies in electronic and bosonic systems have been limited to a Chern number of one. Here, we perform microwave transmission measurements in the bulk and at the edge of ferrimagnetic photonic crystals. Bandgaps with large Chern numbers of 2, 3, and 4 are present in the experimental results which show excellent agreement with theory. We measure the mode profiles and Fourier transform them to produce dispersion relations of the edge modes, whose number and direction match our Chern number calculations.