Coherent manipulation of cold Rydberg atoms near the surface of an atom chip

Abstract

Coherent superpositions of the $49{s}_{1/2}$ and $48{s}_{1/2}$ Rydberg states of cold ${}^{87}$Rb atoms were studied near the surface of an atom chip. The superpositions were created and manipulated using microwaves resonant with the two-photon $49{s}_{1/2}\ensuremath{-}48{s}_{1/2}$ transition. Coherent behavior was observed using Rabi flopping, Ramsey sequences, spin echo, and spin locking. These results are discussed in the context of Rydberg atoms as electric field noise sensors. We consider the coherence of systems quadratically coupled to noise fields with $1/{f}^{\ensuremath{\kappa}}$ power spectral densities ($\ensuremath{\kappa}\ensuremath{\approx}1$).