3D printing of micro-potentials for photonic Bose-Einstein-condensates

Trapping photons in a dye high-Q microcavity comprising two dielectric mirrors allows for studying Bose-Einstein condensation (BEC) of the two-dimensional photon gas under ambient conditions. Adding polymer nanostructures on the surface of the mirrors by direct laser writing provides additional trapping potentials for the photon gas. As the dimensionality of a system profoundly influences its physical behavior, trapping potentials with different effective dimensionality allow to study the modifications of the behavior for the 2d-1d transition. Here, we experimentally study the properties of a harmonically trapped photon gas undergoing Bose-Einstein condensation along this dimensional crossover. By varying the aspect ratio of the harmonic trap, we tune from an isotropic two-dimensional confinement to an anisotropic, highly elongated one-dimensional trapping potential. We discuss the fabrication of the micro potential on the highly reflective dielectric mirrors and determine the caloric properties of the photon gas and discuss prospects of our polymer-based potential landscapes.