Observation of half-quantum vortices in an exciton-polariton condensate.

Lagoudakis, K G; Ostatnický, T; Kavokin, A V; Rubo, Y G; André, R; Deveaud-Plédran, B · Science · 2009

basic_science · Level V

Where this comes from

Abstract

Singly quantized vortices have already been observed in many systems, including the superfluid helium, Bose-Einstein condensates of dilute atomic gases, and condensates of exciton-polaritons in the solid state. Two-dimensional superfluids carrying spin are expected to demonstrate a different type of elementary excitations referred to as half-quantum vortices, characterized by a pi rotation of the phase and a pi rotation of the polarization vector when circumventing the vortex core. We detect half-quantum vortices in an exciton-polariton condensate by means of polarization-resolved interferometry, real-space spectroscopy, and phase imaging. Half-quantum vortices coexist with single-quantum vortices in our sample.