Ridge polariton laser: different from a semiconductor edge-emitting laser

TL;DR

This paper demonstrates a ridge polariton laser with a significantly larger gain and different operational principles compared to conventional edge-emitting lasers, highlighting the unique exciton-polariton interactions in GaN structures.

Contribution

It introduces a novel ridge polariton laser structure and experimentally shows its advantages over traditional lasers, including inversion-less gain and polaritonic mode behavior.

Findings

Achieved laser operation with an exciton reservoir only 15% of the cavity length.

Polaritonic gain is about 10 times larger than in equivalent GaN lasers.

Mode analysis confirms the polaritonic nature of the laser modes.

Abstract

We experimentally demonstrate the difference between a ridge polariton laser, and a conventional edge-emitting ridge laser operating under electron-hole population inversion. The horizontal laser cavities are 20 -- 60 $\mu$m long GaN etched ridge structures with vertical Bragg reflectors. We investigate the laser threshold under optical pumping and assess quantitatively the effect of a varying optically-pumped length. The laser effect is achieved for an exciton reservoir length of just 15% of the cavity length, which would not be possible in a conventional ridge laser, with an inversion-less polaritonic gain about 10 times larger than in equivalent GaN lasers. The modelling of the cavity free spectral range demonstrates the polaritonic nature of the modes.