Polariton lasing in AlGaN microring with GaN/AlGaN quantum wells

TL;DR

This paper demonstrates polariton lasing in the UV range using GaN/AlGaN microring resonators, operating from cryogenic to room temperature, and confirms strong exciton-photon coupling with potential for integrated UV photonic devices.

Contribution

First demonstration of UV polariton lasing in GaN/AlGaN microring resonators across a wide temperature range, confirming strong coupling and low-density lasing.

Findings

Polariton lasing observed in UV spectrum at room temperature.

Strong exciton-photon coupling confirmed by spectral features.

Lasing occurs below the Mott transition density.

Abstract

Microcavity polaritons are strongly interacting hybrid light-matter quasiparticles, which are promising for the development of novel light sources and active photonic devices. Here, we report polariton lasing in the UV spectral range in microring resonators based on GaN/AlGaN slab waveguides, with experiments carried out from 4 K up to room temperature. Stimulated polariton relaxation into multiple ring resonator modes is observed, which exhibit threshold-like dependence of the emission intensity with pulse energy. The strong exciton-photon coupling regime is confirmed by the significant reduction of the free spectral range with energy and the blueshift of the exciton-like modes with increasing pulse energy. Importantly, the exciton emission shows no broadening with power, further confirming that lasing is observed at electron-hole densities well below the Mott transition. Overall, our work paves the way towards development of novel UV devices based on the high-speed slab waveguide polariton geometry operating up to room temperature with potential to be integrated into complex photonic circuits.