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arXiv · 2112.09903

High-resolution coherent probe spectroscopy of a polariton quantum fluid

Ferdinand Claude·Maxime J Jacquet·Romain Usciati·Iacopo Carusotto·Elisabeth Giacobino·Alberto Bramati·Quentin Glorieux
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Abstract

Characterising elementary excitations in quantum fluids is essential to study collective effects within. We present an original angle-resolved coherent probe spectroscopy technique to study the dispersion of these excitation modes in a fluid of polaritons under resonant pumping. Thanks to the unprecedented spectral and spatial resolution, we observe directly the low-energy phononic behaviour and detect the negative-energy modes, i.e. the \textit{ghost branch}, of the dispersion relation. In addition, we reveal narrow spectral features precursory of dynamical instabilities due to the intrinsic out-of-equilibrium nature of the system. This technique provides the missing tool for the quantitative study of quantum hydrodynamics in polariton fluids.

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Ferdinand Claude, Maxime J Jacquet, Romain Usciati, Iacopo Carusotto, Elisabeth Giacobino, Alberto Bramati, Quentin Glorieux. 2021-12-18. High-resolution coherent probe spectroscopy of a polariton quantum fluid. https://doi.org/10.1103/physrevlett.129.103601

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