Bosonic condensation of exciton-polaritons in an atomically thin crystal

TL;DR

This paper demonstrates bosonic condensation of exciton-polaritons in an atomically thin MoSe2 crystal within a microcavity, showing threshold luminescence, spin-polarization, and spatial coherence, advancing coherent light-source technology.

Contribution

It provides the first evidence of exciton-polariton condensation in a monolayer crystal, highlighting novel quantum optical phenomena in two-dimensional materials.

Findings

Observation of threshold-like luminescence increase

Detection of spin-polarizability under magnetic field

Mapping of spatially extended condensate

Abstract

The emergence of two-dimensional crystals has revolutionized modern solid-state physics. From a fundamental point of view, the enhancement of charge carrier correlations has sparked enormous research activities in the transport- and quantum optics communities. One of the most intriguing effects, in this regard, is the bosonic condensation and spontaneous coherence of many-particle complexes. Here, we find compelling evidence of bosonic condensation of exciton-polaritons emerging from an atomically thin crystal of MoSe2 embedded in a dielectric microcavity under optical pumping. The formation of the condensate manifests itself in a sudden increase of luminescence intensity in a threshold-like manner, and a significant spin-polarizability in an externally applied magnetic field. Spatial coherence is mapped out via highly resolved real-space interferometry, revealing a spatially extended condensate. Our device represents a decisive step towards the implementation of coherent light-sources based on atomically thin crystals, as well as non-linear, valleytronic coherent devices.