Ultrafast Oscillations of a Ballistically Propagating Polariton Condensate Driven by Inter-mode Coherent Energy Transfer

TL;DR

This study reveals ultrafast oscillations in a ballistic polariton condensate driven by inter-mode energy transfer, combining experimental time-resolved spectroscopy with theoretical modeling to deepen understanding of nonequilibrium quantum systems.

Contribution

It demonstrates the role of inter-mode coherent energy transfer in inducing ultrafast oscillations in a propagating polariton condensate, supported by both experiments and simulations.

Findings

Observation of ultrafast oscillations with picosecond periods

Identification of inter-mode energy transfer as the oscillation mechanism

Reproduction of experimental results through Gross-Pitaevskii modeling

Abstract

The interplay of dynamics and transport leads to intriguing spatiotemporal behaviors of nonequilibrium macroscopic quantum systems. By means of time-resolved spectroscopy, we here provide microscopic insights into the interplay of ballistic transport and many-particle interactions for an exciton-polariton condensate. We observed anomalous condensation of a coherent polariton flow propagating away from the hot reservoir, accompanied by ultrafast oscillations of its population in the time domain with a period of a few picoseconds. On the basis of time- and spatially-resolved photo luminescence imaging characterization, we reveal that the inter-mode coherent energy transfer, controllable via an incoherent excitonic reservoir, gives rise to the observed ultrafast oscillations. Theoretically, modeling was conducted using an open-dissipative Gross-Pitaevskii equation, with the simulation results fully reproducing our experimental observations. These results advance the fundamental understanding of light-matter interactions in nonequilibrium systems associated with the interplay of dynamics and transport.