Physical Review A
Microwave transitions of pairs of cold Rb Rydberg atoms as Forster resonances of Floquet states
Jeonghun Lee, Javed Iqbal, Thomas F. Gallagher
Abstract
Previous measurements of single photon $n{d}_{5/2}n{d}_{5/2}\ensuremath{\rightarrow}(n+1){d}_{j}(n\ensuremath{-}2)f$ transitions by two of us were described as microwave transitions made possible by configuration interaction (CI) between the $n{d}_{5/2}n{d}_{5/2}$ and the nearly degenerate $(n+2){p}_{3/2}(n\ensuremath{-}2)f$ states [Lee and Gallagher, Phys. Rev. A 93, 062509 (2016)]. Here we report the observation of the one photon $n{d}_{5/2}n{d}_{5/2}\ensuremath{\rightarrow}(n+3){s}_{1/2}(n\ensuremath{-}2)f$, two photon $n{d}_{5/2}n{d}_{5/2}\ensuremath{\rightarrow}(n+3){p}_{j}(n\ensuremath{-}2)f$, and three photon $n{d}_{5/2}n{d}_{5/2}\ensuremath{\rightarrow}(n+4){s}_{1/2}(n\ensuremath{-}2)f$ microwave transitions. We show that both single and multiphoton microwave transitions are conveniently described as Forster resonant energy transfers between resonant Floquet states, and we show that the Floquet-Forster model reduces to the CI model used previously. Finally, to show that the transitions observed previously are by no means unique, we report pair transitions with different initial and final states as well as radio instead of microwave frequencies.