Radiative coupling and weak lasing of exciton-polariton condensates

TL;DR

This paper develops an analytical theory for exciton-polariton condensates in microcavities, revealing a new weak lasing regime characterized by coherent radiation and multiple stable states, explaining several experimental observations.

Contribution

It introduces a novel theoretical framework combining Josephson and radiative couplings to describe condensate arrays and predicts the weak lasing regime with unique stability and symmetry properties.

Findings

Identification of a new weak lasing regime with coherent emission.

Prediction of multiple stable states and switching behavior.

Explanation of experimental puzzles in exciton-polariton systems.

Abstract

In spite of having finite life-time exciton-polaritons in microcavities are known to condense at strong enough pumping of the reservoir. We present an analytical theory of such Bose-condensates on a set of localized one-particle states: condensation centers. To understand physics of these arrays one has to supplement the Josephson coupling by the radiative coupling caused by the interference of the light emitted by different centers. Combination of these couplings with the one-site interaction between the bosons leads to a rich nonlinear dynamics. In particular, a new regime of radiation appears. We call it weak lasing: the centers have macroscopic occupations and radiate coherently, but the coupling alone is sufficient for stabilization. The system can have several stable states and switch between them. Moreover, the time reversal symmetry in this regime is, as a rule, broken. A number of existing experimental puzzles find natural interpretation in the framework of this theory.