Abstract

We present a nonequilibrium phase transition between states of low and high Rydberg occupancy in a room temperature Caesium vapour cell [l]. The phase transition is accompanied by intrinsic optical bistability, and together the phenomena provide an outstanding platform for studying dipole-dipole Rydberg interactions in a thermal vapour. Our work comes at a time of growing interest in Rydberg atoms at room temperature. Observing real-time excitation dynamics has recently shed light on the formation of aggregates [2], whilst new technical advances have seen Rydberg vapours studied in hollow-core fibres [3], and used for electrometry [4].

© 2015 IEEE