Spectroscopy of a cold strontium Rydberg gas

TL;DR

This paper investigates a cold strontium Rydberg gas using laser excitation and ionization detection, providing detailed Stark maps and demonstrating a method to probe gas dynamics with nanosecond resolution.

Contribution

It offers the first detailed Stark maps of strontium Rydberg states and introduces a technique to study Rydberg gas dynamics via autoionization.

Findings

Excellent agreement between measured and calculated Stark maps.

Demonstrated autoionization as a tool for nanosecond-resolved dynamics.

Validated independent-electron model for strontium Rydberg states.

Abstract

We present a study of a cold strontium Rydberg gas. The narrowband laser excitation of Rydberg states in the range n=20-80 from a 6~mK cloud of strontium atoms is detected using the spontaneous ionization of the Rydberg atoms. Using a high-resolution step-scanning technique, we perform detailed measurements of the Stark maps of selected Rydberg states. We find excellent agreement between the measured Stark maps and a numerical calculation based on an independent-electron model. Finally we show that excitation of the second valence electron can be used to probe the dynamics of the Rydberg gas with nanosecond temporal resolution via autoionization.