Topological photonic crystal nanocavity laser

TL;DR

This paper demonstrates a topological photonic crystal nanocavity that supports a single-mode laser with nanoscale confinement, leveraging topological edge states to achieve predictable mode control and enhanced light-matter interaction.

Contribution

It introduces a topological nanocavity with a near-diffraction-limited mode volume that guarantees a single mode, advancing the miniaturization of topological photonic devices.

Findings

Achieved single-mode lasing in a topological nanocavity.

Demonstrated high spontaneous emission coupling factor.

Realized nanoscale topological photonic confinement.

Abstract

Topological edge states exist at the interfaces between two topologically-distinct materials. The presence and number of such modes are deterministically predicted from the bulk-band topologies, known as the bulk-edge correspondence. This principle is highly useful for predictably controlling optical modes in resonators made of photonic crystals (PhCs), leading to the recent demonstrations of micro-scale topological lasers. Meanwhile, zero-dimensional topological trapped states in the nanoscale remained unexplored, despite its importance for enhancing light-matter interactions and for wide applications including single-mode nanolasers. Here, we report a topological PhC nanocavity with a near-diffraction-limited mode volume and its application to single-mode lasing. The topological origin of the nanocavity, formed at the interface between two topologically-distinct PhCs, guarantees the existence of only one mode within its photonic bandgap. The observed lasing accompanies a high spontaneous emission coupling factor stemming from the nanoscale confinement. These results encompass a way to greatly downscale topological photonics.