Observation of Half-Quantum Vortices in an Exciton-Polariton Condensate

K. G. Lagoudakis , T. Ostatnicky , A.V. Kavokin , Yuri G. Rubo (1) , Régis André (2) , Benoit Deveaud-Plédran (3)

1 Centro de Investigación en Energía
2 NEEL - NPSC - Nanophysique et Semiconducteurs
3 Institute of Condensed Matter Physics [Lausanne]

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 p rotation of the phase and a p 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

K. G. Lagoudakis, T. Ostatnicky, A.V. Kavokin, Yuri G. Rubo, Régis André, et al.. Observation of Half-Quantum Vortices in an Exciton-Polariton Condensate. Science, 2009, 326 (5955), pp.974-976. ⟨10.1126/science.1177980⟩. ⟨hal-01016992⟩