Sub-Doppler spectroscopy of Rydberg atoms via velocity selection memory in a hot vapor cell

TL;DR

This paper demonstrates sub-Doppler spectroscopy of Rydberg states in a hot vapor cell by leveraging velocity selection memory effects, revealing detailed spectral features despite thermalization.

Contribution

It introduces a simple pump-probe method to perform sub-Doppler Rydberg spectroscopy in hot vapor cells, highlighting the persistence of velocity selection amidst thermalization.

Findings

Velocity selection survives in hyperfine levels despite thermalization

Sub-Doppler resolution achieved in a hot vapor cell

Spectral analysis reveals collisional shifts and broadenings

Abstract

We study resonance redistribution mechanisms inside a hot vapor cell. This is achieved by pumping atoms on the first cesium resonance, 6S1/2-->6P1/2, and subsequently probing the velocity distribution of the 6P1/2 population by a linear absorption experiment on the 6P1/2-->16S1/2 or 6P1/2-->15D3/2 transitions at 514 nm and 512 nm respectively. We demonstrate that despite the existence of thermalization processes, traces of the initial velocity selection, imposed by the pump, survive in both hyperfine levels of the intermediate (6P1/2) state. This observation, allows us to perform sub-Doppler resolution vapor cell spectroscopy on Rydberg states using a simple pump-probe setup. At high cesium densities, redistribution mechanisms dominate, and the velocity selection vanishes. However, spectral analysis provides information on the collisional shifts and broadenings of the probed Rydberg states.