# Paschen-Back effect and Rydberg-state diamagnetism in vapor-cell electromagnetically induced transparency

## TL;DR

This paper investigates Rydberg electromagnetically induced transparency in rubidium vapor under a strong magnetic field, revealing isotope-specific signals, precise magnetic field measurement capabilities, and large dephasing rates, supported by theoretical modeling.

## Contribution

It demonstrates Rydberg-EIT in a hyperfine Paschen-Back regime with isotope-mixed cells, enabling accurate magnetic field measurement and revealing large dephasing effects not previously characterized.

## Key findings

- Achieved EIT signals in a 0.7 T magnetic field in rubidium vapor.
- Measured magnetic field with a relative uncertainty of ±0.12%.
- Observed unexpectedly large Rydberg-level dephasing rates.

## Abstract

We report on rubidium vapor-cell Rydberg electromagnetically induced transparency (EIT) in a 0.7~T magnetic field where all involved levels are in the hyperfine Paschen-Back regime, and the Rydberg state exhibits a strong diamagnetic interaction with the magnetic field. Signals from both $^{85}\mathrm{Rb}$ and $^{87}\mathrm{Rb}$ are present in the EIT spectra. This feature of isotope-mixed Rb cells allows us to measure the field strength to within a $\pm 0.12$\% relative uncertainty. The measured spectra are in excellent agreement with the results of a Monte Carlo calculation and indicate unexpectedly large Rydberg-level dephasing rates. Line shifts and broadenings due to small inhomogeneities of the magnetic field are included in the model.