Relaxation Oscillations of an Exciton-polariton Condensate Driven by Parametric Scattering

TL;DR

This paper demonstrates the observation and theoretical modeling of relaxation oscillations in an exciton-polariton condensate caused by parametric scattering, revealing high stability and efficiency in the process.

Contribution

It provides the first experimental observation and theoretical analysis of relaxation oscillations driven by parametric scattering in exciton-polariton condensates.

Findings

Observation of coherent oscillations in polariton condensates

Excellent agreement between experiments and Gross-Pitaevskii simulations

High stability of relaxation oscillations despite multiple excitation pulses

Abstract

We report observation of coherent oscillations in the relaxation dynamics of an exciton-polariton condensate driven by parametric scattering processes. As a result of the interbranch scattering scheme and the nonlinear polariton-polariton interactions, such parametric scatterings exhibit high scattering efficiency, which leads to fast depletion of the polariton condensate and periodic shut-off of the bosonic stimulation processes, eventually causing relaxation oscillations. Employing polariton-reservoir interactions, the oscillation dynamics in the time domain can be projected onto the energy space. In theory, our simulations using the open-dissipative Gross-Pitaevskii equation are in excellent agreement with experimental observations. Surprisingly, the oscillation patterns are clearly visible in our time-integrated images including many excitation pulses, implying the high stability of the relaxation oscillations driven by polariton parametric scatterings.