Anomalous broadening in driven dissipative Rydberg systems

TitleAnomalous broadening in driven dissipative Rydberg systems
Publication TypeJournal Article
Year of Publication2016
AuthorsGoldschmidt, EA, Boulier, T, Brown, RC, Koller, SB, Young, JT, Gorshkov, AV, Rolston, SL, Porto, JV
JournalPhysical Review Letters
Date Published2016/03/16

We observe interaction-induced broadening of the two-photon 5s-18s transition in 87Rb atoms trapped in a 3D optical lattice. The measured linewidth increases by nearly two orders of magnitude with increasing atomic density and excitation strength, with corresponding suppression of resonant scattering and enhancement of off-resonant scattering. We attribute the increased linewidth to resonant dipole-dipole interactions of 18s atoms with spontaneously created populations of nearby np states. Over a range of initial atomic densities and excitation strengths, the transition width is described by a single function of the steady-state density of Rydberg atoms, and the observed resonant excitation rate corresponds to that of a two-level system with the measured, rather than natural, linewidth. The broadening mechanism observed here is likely to have negative implications for many proposals with coherently interacting Rydberg atoms.