McQuillen, P.Zhang, X.Strickler, T.Dunning, F.B.Killian, T.C.2013-01-282013-01-282013McQuillen, P., Zhang, X., Strickler, T., et al.. "Imaging the evolution of an ultracold strontium Rydberg gas." <i>Physical Review A,</i> 87, (2013) American Physical Society: 13407. http://dx.doi.org/10.1103/PhysRevA.87.013407.https://hdl.handle.net/1911/69854Clouds of ultracold strontium 5s48s1S0 or 5s47d1D2 Rydberg atoms are created by two-photon excitation of laser-cooled 5s21S0 atoms. The spontaneous evolution of the cloud of low orbital angular momentum (low-ℓ) Rydberg states towards an ultracold neutral plasma is observed by imaging resonant light scattered from core ions, a technique that provides both spatial and temporal resolution. Evolution is observed to be faster for the S states, which display isotropic attractive interactions, than for the D states, which exhibit anisotropic, principally repulsive interactions. Immersion of the atoms in a dilute ultracold neutral plasma speeds up the evolution and allows the number of Rydberg atoms initially created to be determined.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttp://dx.doi.org/10.1103/PhysRevA.87.013407