High-Precision Measurement of Rydberg State Hyperfine Splitting in a Room-Temperature Vapour Cell

TL;DR

This paper demonstrates high-precision measurements of Rydberg state hyperfine splittings in rubidium 87 using EIT spectroscopy at room temperature, achieving sub-natural linewidth resolution and high accuracy.

Contribution

The authors introduce a novel EIT-based method for measuring Rydberg hyperfine splittings with unprecedented accuracy at room temperature.

Findings

Hyperfine splittings measured with ~100 kHz accuracy

Line-widths of 3.7 MHz achieved despite Doppler-broadening

Method enables future high-precision Rydberg state studies

Abstract

We present direct measurements of the hyperfine splitting of Rydberg states in rubidium 87 using Electromagnetically Induced Transparency (EIT) spectroscopy in a room-temperature vapour cell. With this method, and in spite of Doppler-broadening, line-widths of 3.7 MHz FWHM, i.e. significantly below the intermediate state natural linewidth are reached. This allows resolving hyperfine splittings for Rydberg s-states with n=20...24. With this method we are able to determine Rydberg state hyperfine splittings with an accuracy of approximately 100 kHz. Ultimately our method allows accuracies of order 5 kHz to be reached. Furthermore we present a direct measurement of hyperfine-resolved Rydberg state Stark-shifts. These results will be of great value for future experiments relying on excellent knowledge of Rydberg-state energies and