Polarization-insensitive microwave electrometry using Rydberg atoms

We investigate the Autler-Townes splitting for Rydberg atoms dressed with linearly polarized microwave radiation, resonant with generic ${S}_{1/2}\ensuremath{\leftrightarrow}{P}_{1/2}$ and ${S}_{1/2}\ensuremath{\leftrightarrow}{P}_{3/2}$ transitions. The splitting is probed using laser light via electromagnetically induced transparency measurements, where the transmission of probe laser light reveals a two-peak pattern. In particular, this pattern is invariant under rotation of the microwave field polarization. In consequence, we establish $S\ensuremath{\leftrightarrow}P$ Rydberg transitions as ideally suited for polarization-insensitive electrometry, contrary to recent findings [A. Chopinaud and J. D. Pritchard, Phys. Rev. Appl. 16, 024008 (2021)].