Pascal Gerry Mickelson

Using absorption imaging to study ion dynamics in an ultracold neutral plasma

We report optical absorption imaging of ultracold neutral strontium plasmas. The ion absorption spectrum determined from the images is Doppler broadened and thus provides a quantitative measure of the ion kinetic energy. For the particular plasma conditions studied, ions heat rapidly as they equilibrate during the first 250 ns after plasma formation. Equilibration leaves ions on the border between the weakly coupled gaseous and strongly coupled liquid states. On a longer time scale of microseconds, pressure exerted by the trapped electron gas accelerates the ions radially.

Observation of an optical Feshbach resonance in 88 Sr

We have tuned the s-wave scattering length of 88Sr via an optical Feshbach resonance. Change in the rate of thermalization of atoms reveals a slight increase in the phase space density of the atom sample.