Transition from propagating polariton solitons to a standing wave condensate induced by interactions

TL;DR

This paper investigates how polariton wavepackets transition from propagating solitons to a standing wave condensate in a microwire system, revealing the role of interactions and density in these nonlinear phenomena.

Contribution

It demonstrates the sequential transition from propagating wavepackets to solitons and then to a standing wave condensate driven by polariton interactions and density effects.

Findings

Ballistic propagation at low density

Formation of bright solitons at intermediate density

Emergence of a standing wave condensate at high density

Abstract

We explore nonlinear transitions of polariton wavepackets, first, to a soliton and then to a standing wave polariton condensate in a multi-mode microwire system. At low polariton density we observe ballistic propagation of the multi-mode polariton wavepackets arising from the interference between different transverse modes. With increasing polariton density, the wavepackets transform into single mode bright solitons due to effects of both inter-modal and intra-modal polariton-polariton scattering. Further increase of the excitation density increases thermalisation speed leading to relaxation of the polariton density distribution in momentum space with the resultant formation of a non-equilibrium condensate manifested by a standing wave pattern across the whole sample.