Data associated with "Resolving magnetic-sublevel structure in Rydberg Autler-Townes spectra with arbitrary RF polarization"

We investigate the role of magnetic sublevels in Autler–Townes spectra of Rydberg atoms driven by radio-frequency (RF) fields with arbitrary polarization. While conventional treatments predict two symmetric sidebands from independent $m_J$ transitions, experiments have reported additional unexplained spectral features. We show that these arise from elliptical RF polarization, which coherently couples multiple magnetic sublevels and requires a full multi-level treatment. We develop and diagonalize a Hamiltonian including all coupled m_J sublevels, predicting polarization-dependent degeneracies that produce two, three, or four resolved peaks. Using long-wavelength transitions and an anechoic environment we realize homogeneous RF fields that for the first time enable complete resolution of the m_J-dependent dressed states. We observe excellent agreement with theory as the RF ellipticity is varied. These results demonstrate that RF polarization fundamentally modifies Autler–Townes spectra and provide a consistent framework for interpreting magnetic-sublevel structure, with implications for Rydberg-based RF electrometry and polarimetry.