Quantify the impact of Rydberg-state excitation on effective RF permittivity

Determine the quantitative change in the effective complex RF permittivity of a rubidium-87–filled quartz vapor cell measured in a stripline transmission-line setup when a fraction of the atoms are excited to Rydberg states, beyond the observed sub-1% differences in calibrated S-parameters across the measurement band.

Background

The study introduces a stripline-based method to extract effective complex RF permittivity for various alkali-filled vapor cells from 10–300 MHz. To probe whether the act of optical excitation to Rydberg states alters these effective properties, the authors measured S-parameters with a fraction of atoms in the excited Rydberg state and observed less than a 1% change in magnitude.

While this suggests only a small effect, the authors explicitly state that they could not quantify the corresponding change in effective complex permittivity. They note that only a small fraction of atoms were excited and suggest that the outcome may depend on atomic configuration and frequency, motivating further targeted measurements and analysis.