Parity anomaly and Landau-level lasing in strained photonic honeycomb lattices

TL;DR

This paper explores how strain-induced Landau levels in photonic honeycomb lattices lead to unique amplification and localization effects, influenced by parity anomaly, impacting laser mode selection and beam dynamics.

Contribution

It reveals the role of parity anomaly in Landau-level formation and its effects on lasing properties in strained photonic honeycomb lattices, a novel insight in topological photonics.

Findings

Landau-level-like amplified states form in strained lattices

Parity anomaly causes zeroth Landau level localization on a single sublattice

Anomaly influences mode selection and lasing thresholds

Abstract

We describe the formation of highly degenerate, Landau-level-like amplified states in a strained photonic honeycomb lattice in which amplification breaks the sublattice symmetry. As a consequence of the parity anomaly, the zeroth Landau level is localized on a single sublattice and possesses an enhanced or reduced amplification rate. The spectral properties of the higher Landau levels are constrained by a generalized time-reversal symmetry. In the setting of two-dimensional photonic crystal lasers, the anomaly directly affects the mode selection and lasing threshold while in three-dimensional photonic lattices it can be probed via beam dynamics.