Rydberg blockade in an ultracold strontium gas revealed by two-photon excitation dynamics
Abstract
We demonstrate the interaction-induced blockade effect in an ultracold 88Sr gas via studying the time dynamics of a two-photon excitation to the triplet Rydberg series 5sns\, 3S1 for five different principle quantum numbers n ranging from 19 to 37. By using a multi-pulse excitation sequence to increase the detection sensitivity we could identify Rydberg-excitation-induced atom losses as low as <1\%. Based on an optical Bloch equation formalism, treating the Rydberg-Rydberg interaction on a mean-field level, the van der Waals coefficients are extracted from the observed dynamics, which agree fairly well with ab initio calculations.
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