Photon thermalization and a condensation phase transition in an electrically pumped semiconductor microresonat

TL;DR

This study demonstrates photon thermalization and Bose-Einstein condensation in a semiconductor microresonator at room temperature, revealing a phase transition characterized by specific spectral and population behaviors.

Contribution

First experimental observation of photon Bose-Einstein condensation in a semiconductor microresonator under electrical pumping at room temperature.

Findings

Photon thermalization observed in a semiconductor microresonator.

Identification of a phase transition at phase-space density of order unity.

Evidence of Bose-Einstein condensation of photons in equilibrium with a reservoir.

Abstract

We report on an experimental study of photon thermalization and condensation in a semiconductor microresonator in the weak-coupling regime. We measure the dispersion relation of light and the photon mass in a single-wavelength, broad-area resonator. The observed luminescence spectrum is compatible with a room-temperature, thermal-equilibrium distribution. A phase transition, identified by a saturation of the population at high energies and a superlinear increase of the occupation at low energy, takes place when the phase-space density is of order unity. We explain our observations by Bose-Einstein condensation of photons in equilibrium with a particle reservoir and discuss the relation with laser emission.