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arXiv · 1103.1488

From single particle to superfuid excitations in a dissipative polariton gas

Verena Kohnle·Yoan Léger·Michiel Wouters·Maxime Richard·Marcia T. Portella-Oberli·Benoit Deveaud-Plédran
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Abstract

Using angle-resolved heterodyne four-wave-mixing technique, we probe the low momentum excitation spectrum of a coherent polariton gas. The experimental results are well captured by the Bogoliubov transformation which describes the transition from single particle excitations of a normal fluid to sound-wave-like excitations of a superfluid. In a dense coherent polariton gas, we find all the characteristics of a Bogoliubov transformation, i.e. the positive and negative energy branch with respect to the polariton gas energy at rest, sound-wave-like shapes for the excitations dispersion, intensity and linewidth ratio between the two branches in agreement with the theory. The influence of the non-equilibrium character of the polariton gas is shown by a careful analysis of its dispersion.

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Verena Kohnle, Yoan Léger, Michiel Wouters, Maxime Richard, Marcia T. Portella-Oberli, Benoit Deveaud-Plédran. 2011-03-08. From single particle to superfuid excitations in a dissipative polariton gas. https://doi.org/10.1103/physrevlett.106.255302

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