Physical Review A
Two-photon microwave transitions and strong-field effects in a room-temperature Rydberg-atom gas
David Alexander Anderson, Andrew Schwarzkopf, Stephanie Miller, Nithiwadee Thaicharoen, Georg A. Raithel, Joshua A. Gordon, Christopher L. Holloway
Abstract
We investigate two-photon Autler-Townes splitting and strong-field effects of $^{85}\mathrm{Rb}$ Rydberg atoms in a room-temperature vapor cell. To observe the level structure we employ electromagnetically induced transparency. We first study the two-photon $62{S}_{1/2}\text{\ensuremath{-}}63{S}_{1/2}$ microwave transition using an electric-field reference measurement obtained with the one-photon $62{S}_{1/2}\text{\ensuremath{-}}62{P}_{3/2}$ transition. We then study the $61{D}_{5/2}\text{\ensuremath{-}}62{D}_{5/2}$ transition where the microwave electric-field range is extended up to $\ensuremath{\sim}40\phantom{\rule{0.28em}{0ex}}\mathrm{V}/\mathrm{m}$. A Floquet analysis is used to model field-induced level shifts and state-mixing effects present in the strongly driven quantum systems under consideration. Calculations are found to be in good agreement with experimental observations.