2011/03/08 by Verena Kohnle, V. Kohnle, Yoan Léger +6 · 104 citations
Engineering · Physics and Astronomy · #Atomic physics #Condensed matter physics #Dispersion (optics) #Dissipative system #Excitation #Laser #Laser linewidth #Physics #Polariton #Quantum Electrodynamics and Casimir Effect #Quantum mechanics #Quasiparticle #Strong Light-Matter Interactions #Superconductivity #Superfluidity #Thermal Radiation and Cooling Technologies #cond-mat.other #cond-mat.quant-gas
paper · pdf · doi:10.1103/physrevlett.106.255302
published in Physical Review Letters 106(25), 255302 (American Physical Society) · 4 pages, 3 figures
arxiv created 2011/03/08 · openalex publication_date 2011/06/22 · arxiv updated 2015/05/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Using an 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 soundlike 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, soundlike shapes for the excitations dispersion, intensity, and linewidth ratio between the two branches in agreement with the theory. The influence of the nonequilibrium character of the polariton gas is shown by a careful analysis of its dispersion.