Topological Laser in Anomalous Quadrupole Topological Phases

TL;DR

This paper demonstrates the first experimental topological laser in an anomalous quadrupole topological phase, showcasing corner states and single-mode pulsed lasing in a nanocavity at telecommunication wavelengths.

Contribution

It provides the first experimental realization of a topological laser in an anomalous quadrupole phase using a twisted nanocavity with high quality factor.

Findings

Observation of corner states in the topological nanocavity

Achievement of single-mode pulsed lasing at telecommunication wavelengths

Lasing threshold of 23 μW with a quality factor of 1,500

Abstract

Topological photonics shows considerable promise in revolutionizing photonic devices through the use of topological phases, leading to innovations like topological lasers that enhance light control. One of recent breakthroughs is reducing the size of these systems by utilizing lower-dimensional boundary states, notably via higher-order topological phases. This paper presents the first experimental demonstration of topological laser in anomalous quadrupole topological phase, an instance of higher-order phases. To facilitate this, a topological nanocavity with quality factor near 6,000 is engineered through a twisting operation. The topological nature of our system is validated by calculation of nested Wannier center and the emergency condition of corner states. Our experimental observations reveal the manifestation of corner states and the achievement of single-mode pulsed laser, driven by optical gain from multiple quantum wells at telecommunication wavelengths and at a temperature of 4 K. A lasing threshold of 23 uW and a cold quality factor of 1,500 are deduce through rate equation. Our work gives a new potential in the application of topological principles to advance nanophotonic technologies.