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Séminaire de Robert Nyman

Bose-Einstein condensation of just a few photons

27/04/2018   :   11h00
Sophia Antipolis
Publication : 27/04/2018
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Photons in a dye-filled microcavity reach thermal equilibrium through multiple emission and re-absorption events from a fluorescent dye. With sufficient population, Bose-Einstein condensation (BEC) occurs, leading to macroscopic occupation of the lowest-energy cavity mode. I will explore the breakdown of thermalisation when the photon re-absorption rate becomes low compared to cavity loss. We observe multi-mode condensation. The system is shows a rich non-equilibrium phase diagram which demonstrates how photon BEC crosses over to normal laser operation. Decondensation, where a mode's population dramatically decreases with increasing pump rate, is predicted [HJ Hesten, RA Nyman, and F Mintert, Phys. Rev. Lett. 120, 040601 (2018)]. We have recently demonstrated BEC of just 7 photons, taking the BEC phase transition to a new regime [BT Walker, et al (RA Nyman), arXiv:1711.11087].