Polarization impact on sensitivity of Rydberg atom-based microwave sensors

We investigate the sensitivity of a Rydberg atom-based microwave sensor under two polarization configurations as a function of local oscillator (LO) microwave field strength. By employing parallel and perpendicular alignments of laser and microwave polarizations in our experimental setup, we study the Autler–Townes (AT) splitting spectrum and optical response of probe transmission, and analyze their sensing effects. The results show that the parallel polarization configuration offers higher gain and better sensitivity than the perpendicular configuration. We achieve a sensitivity of 4.150(69) nV⋅cm⁻¹⋅Hz^−1/2 at an LO microwave field strength of 1.74 mV/cm. This work demonstrates the significant role of polarization alignment on the performance of Rydberg atom-based microwave sensors.