Quantum degeneracy of microcavity polaritons

TL;DR

This paper experimentally demonstrates quantum degeneracy in microcavity polaritons, showing macroscopic population in a quantum state, polariton scattering transfer, and evidence of spatial coherence.

Contribution

It provides new experimental evidence of quantum degeneracy and coherence in exciton polaritons within semiconductor microcavities.

Findings

Resonant pumping creates a macroscopic polariton population in a single quantum state.

Parametric scattering transfers polaritons between quantum states.

Direct evidence of spatial coherence in the transferred polariton population.

Abstract

We investigate experimentally one of the main features of a quantum fluid constituted by exciton polaritons in a semiconductor microcavity, that is quantum degeneracy of a macroscopic fraction of the particles. We show that resonant pumping allows to create a macroscopic population of polaritons in one quantum state. Furthermore we demonstrate that parametric polariton scattering results in the transfer of a macroscopic population of polariton from one single quantum state into another one. Finally we briefly outline a simple method which provides direct evidence of the first-order spatial coherence of the transferred population.