Imaging the evolution of an ultracold strontium Rydberg gas

TL;DR

This study visualizes the dynamic evolution of ultracold strontium Rydberg gases into neutral plasmas, revealing state-dependent interaction effects and the influence of an ultracold plasma environment.

Contribution

It introduces a resonant light scattering imaging technique to observe real-time evolution of Rydberg gases into plasmas with spatial and temporal resolution.

Findings

Faster evolution for S-states due to isotropic attractive interactions

D-states evolve more slowly because of anisotropic, mainly repulsive interactions

Presence of ultracold plasma accelerates the Rydberg gas evolution

Abstract

Clouds of ultracold strontium 5s48s 1S0 or 5s47d 1D2 Rydberg atoms are created by two photon excitation of laser cooled 5s2 1S0 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.