Modeling Line Broadening and Distortion Due to Spatially Non-Uniform Fields in Rydberg Electrometry

TL;DR

This paper introduces a model for predicting spectral broadening and distortion in Rydberg atom electromagnetically-induced transparency caused by spatially non-uniform electric fields, aiding in accurate field measurement.

Contribution

The authors develop a multi-layered Beer's law-based model to simulate spectral broadening due to non-uniform fields in Rydberg electrometry, applicable to various optical parameter distributions.

Findings

Model accurately replicates experimental spectral broadening.

Field non-uniformity causes measurable spectral distortion.

Applicable to standing wave and environmental reflection scenarios.

Abstract

We present a model for calculating broadened Autler-Townes spectra when probing ac electric field magnitudes by use of Rydberg atom electromagnetically-induced transparency. This model approximates the atom vapor as a multi-layered media and uses Beer's law to combine probe beam absorption through many discrete thin segments, replicating the broadening seen in experimental measurements. The methodology can be easily applied to other non-uniform optical parameters when monitoring total spectral transmission or phase delay. Field non-uniformity is present in standing waves of unmatched waveguides and glass vapor cells, which are generally due to source characteristics and environmental reflections. We present broadening and distortion effects caused by various types of electric-field distributions, and compare this model to results obtained from measured atomic spectra.