Le vendredi 27 octobre à 14H en vidéoconférence : (Meeting ID: 922 7236 0416 – Secret code: KuS8G9) https://zoom.us/j/92272360416?pwd=K3BZb2hFQXRkb1pYeEdCN29FUGRydz09#success

Generation, propagation and control of quantized vortices and dark solitons in polariton superfluids

Exciton-polaritons are quasi-particles arising from the strong coupling regime between excitons and photons. In planar microcavitites, phenomena such as superfluidity or Bose-Einstein condensation can be observed. Those systems have demonstrated to be very efficient in the hydrodynamic generation of topological excitations, such as vortex-antivortex pairs or dark solitons. However, the lifetime and motion of those excitations were limited by the driven dissipative nature of the system.
In this thesis, we present a rich variety of results about the generation and control of
such topological excitations. Taking advantage of the optical bistability present in our system, we were able to greatly enhanced the propagation length of vortices and solitons generated in the wake of a structural defect, revealing in the mean time an unexpected binding mechanism of the solitons which propagate parallel.
This behaviour was recovered in  a specifically designed  experiment, where we artificially imprint dark soliton pairs on demand on a polariton superfluid. The adaptability of our technique allowed for a detailed study of this phenomenon, that we directly connected to the driven-dissipative nature of our system.
Finally, confined dark solitons were generated within guided intensity channels on a static polariton fluid. The absence of flow lead to the development of transverse snake instabilities of which we studied the interesting properties.