Relaxation Oscillations of an Exciton–Polariton Condensate Driven by Parametric Scattering

Abstract

We report the observation of coherent oscillations in the relaxation dynamics of an exciton–polariton condensate that were driven by parametric scattering processes. As a result of the interbranch scattering scheme and the nonlinear polariton–polariton interactions, such parametric scatterings exhibit a high scattering efficiency that leads to the fast depletion of the polariton condensate and the 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, including many excitation pulses, are clearly visible in our time-integrated images, implying the high stability of the relaxation oscillations driven by polariton parametric scatterings.

Exciton-polariton parametric scattering in quasi-one-dimensional system

“…In a prior study, we demonstrated the strong coupling between excitons and cavity photons in the ZnO WGM system [5,22] . To isolate the measurement to the exciton-polaritons inside the pump region, a filtering optical system as shown in Figure 2 was employed.…”

“…This has been widely reported in previous literature [1,2,4,5,26] . As exciton polaritons are a hybrid state of excitons and photons, they must have the characteristic of particle-particle scattering, the most famous of which is parametric scattering, which has been widely reported in other literature [16][17][18][19][20][21][22] .…”

“…Unlike the Bose-Einstein condensate of an ideal gas, the exciton component of the exciton-polariton condensate renders scattering between the exciton-polariton. Like conventional particles, this scattering between particles includes irregular scattering, four-wave mixing [15] , and parametric scattering [16][17][18][19][20][21][22] . In conventional particles, irregular scattering dominates.…”

Spin-Polarization-Induced Chiral Polariton Lasing at Room Temperature

“…Recent findings strongly suggest that the wide-band gap semiconductor microcavity is a feasible system for breaking through the temperature bottleneck of polaritonic devices. 23,24 Due to its intrinsically large exciton binding energy and giant oscillator strength, polariton BEC can be preserved at considerably higher temperatures. In fact, room temperature (RT) polariton lasing has already been realized in a wide band gap ZnO nanoplate, as reported in our previous work.…”

“…For example, spin-polarized polariton lasing has been reported in GaAs/CdTe-based quantum well microcavities. − However, ultra-low operation temperature is an inevitable limitation for polariton applications using conventional GaAs/CdTe. Recent findings strongly suggest that the wide-band gap semiconductor microcavity is a feasible system for breaking through the temperature bottleneck of polaritonic devices. , Due to its intrinsically large exciton binding energy and giant oscillator strength, polariton BEC can be preserved at considerably higher temperatures. In fact, room temperature (RT) polariton lasing has already been realized in a wide band gap ZnO nanoplate, as reported in our previous work .…”