Bose-Einstein condensation of photons from the thermodynamic limit to small photon numbers

Robert A. Nyman, Benjamin T. Walker
2017 Journal of Modern Optics  
Photons can come to thermal equilibrium at room temperature by scattering multiple times from a fluorescent dye. By confining the light and dye in a microcavity, a minimum energy is set and the photons can then show Bose-Einstein condensation. We present here the physical principles underlying photon thermalization and condensation, and review the literature on the subject. We then explore the 'small' regime where very few photons are needed for condensation. We compare thermal equilibrium
more » ... ts to a rate-equation model of microlasers, which includes spontaneous emission into the cavity, and we note that small systems result in ambiguity in the definition of threshold.
doi:10.1080/09500340.2017.1404655 fatcat:roobpbvnj5ccrp2mjhn2qg5ngu