Absolute frequency measurements of 85Rb nF7/2 Rydberg states using purely optical detection

TL;DR

This paper reports the first absolute frequency measurements of 85Rb Rydberg states using purely optical detection, achieving high accuracy and demonstrating robustness to electric fields.

Contribution

It introduces a novel purely optical detection scheme for absolute frequency measurements of rubidium Rydberg states, with high precision and stability.

Findings

Achieved measurement accuracy of 8.0 MHz.

Demonstrated high frequency stability of Rydberg levels.

Showed robustness of Rydberg states to electric fields.

Abstract

A three-step laser excitation scheme is used to make absolute frequency measurements of highly excited nF7/2 Rydberg states in 85Rb for principal quantum numbers n=33-100. This work demonstrates the first absolute frequency measurements of rubidium Rydberg levels using a purely optical detection scheme. The Rydberg states are excited in a heated Rb vapour cell and Doppler free signals are detected via purely optical means. All of the frequency measurements are made using a wavemeter which is calibrated against a GPS disciplined self-referenced optical frequency comb. We find that the measured levels have a very high frequency stability, and are especially robust to electric fields. The apparatus has allowed measurements of the states to an accuracy of 8.0MHz. The new measurements are analysed by extracting the modified Rydberg-Ritz series parameters.