Measurement and numerical calculation of Rubidium Rydberg Stark spectra

TL;DR

This study measures and calculates Stark-shifted energy levels of rubidium Rydberg atoms in high electric fields using EIT, extending previous verification to higher quantum numbers and field strengths with high precision.

Contribution

It provides new experimental Stark maps for high n Rydberg states and validates ab initio calculations at higher quantum numbers and electric fields.

Findings

Stark maps for n=35 and n=70 were obtained with high signal-to-noise ratio.

Theoretical calculations agree with experimental data within 2 MHz accuracy.

The work extends the validation of numerical methods to higher quantum numbers and electric fields.

Abstract

We report on the measurement of Stark shifted energy levels of $^{87}$Rb Rydberg atoms in static electric fields by means of electromagnetically induced transparency (EIT). Electric field strengths of up to 500V/cm, ranging beyond the classical ionisation threshold, were applied using electrodes inside a glass cell with rubidium vapour. Stark maps for principal quantum numbers $n=35$ and $n=70$ have been obtained with high signal-to-noise ratio for comparison with results from ab initio calculations following the method described in [M. L. Zimmerman et al., Phys. Rev. A 20, 2251 (1979)], which was originally only verified for states around $n=15$. We also calculate the dipole matrix elements between low-lying states and Stark shifted Rydberg states to give a theoretical estimate of the relative strength of the EIT signal. The present work significantly extends the experimental verification of this numerical method in the range of both high principal quantum numbers and high electric fields with an accuracy of up to 2MHz.