Relaxation Oscillations of an Exciton–Polariton Condensate Driven by Parametric Scattering
Chuan Tian, Linqi Chen, Yingjun Zhang, Liqing Zhu, Wenping Hu, Yichun Pan, Zheng Wang, Fangxin Zhang, Long Zhang, Hongxing Dong, Weihang Zhou
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.