Polariton Bose-Einstein Condensates in a snapshot:
Bose-Einstein condensation (BEC) is an exotic state of matter, wherein particles coalesce to a macroscopically occupied coherent state. BECs have been observed for a broad range of systems such as 4He, alkali-metal atoms, magnons, and polaritons. Beyond the beauty of the underlying physics describing the fundamental properties and dynamics of BECs, there is a range of applications that utilise the coherence of their massive wavefunctions, especially in the rapidly developing field of quantum technologies. In semiconductor microcavities, polaritons result from the admixture of cavity photons and excitons in the strong coupling regime. Above a critical density, polaritons have been shown to undergo BEC. Unlike other BECs, polariton condensates (hosted in semiconductor slabs embedded in optical cavities) can be optically pumped, while they decay by emitting coherent light, very much like an optically pumped laser. By appropriate choice of the crystalline semiconductor host, polariton condensates can form even at room temperature. Our research in the field of polaritonics spans a broad range of fundamental physics and applications including polariton simulators, polariton circuits and room temperature polaritonics.
Animated introduction to the concept of polaritons from our EPSRC Programme Grant on Hybrid Polaritonics website: