Orateur
Description
Cavity polaritons are hybrid exciton-photon quasi-particles emerging from the strong
coupling regime between photons confined in an optical cavity and excitons confined in
quantum wells. They present physical properties reflecting their mixed nature. From
the photon part, they inherit a small effective mass and can be confined in lattices with
typical dimensions of the order of a few microns. Their excitonic part endows them
with inter-particle interactions resulting in a giant Kerr non linearity. Cavity polaritons
exhibit fascinating properties such as Bose Einstein condensation at elevated temperature,
superfluidity, multistability... Importantly, the system is driven-dissipative in nature: the
driving field maintains an out-of-equilibrium steady-state by compensating the constant
leakage of photons.
Recent theoretical works have shown that the phase dynamics of out-of-equilibrium
condensates obeys the celebrated Kardar Parisi Zhang (KPZ) equation [1-3]. In this
talk, I will present our recent experimental observation of universal KPZ scaling laws in
the first order coherence of a 1D polariton condensate [4]. I will first explain how we
generated highly elongated polariton condensates in a 1D polariton lattice. I will then
describe our measurements of the condensate coherence. Finally, I will show that data
points lying within a well-defined spatio-temporal window collapse onto a single scaling
function, characteristic of the KPZ universality class.
