Electric field sensing near the surface microstructure of an atom chip using cold Rydberg atoms

J.D. Carter, J.D.D. Martin

J. D. Carter, Owen Cherry, J. D. D. Martin

The electric fields near the heterogeneous metal-dielectric surface of an atom chip were measured using cold atoms. The atomic sensitivity to electric fields was enhanced by exciting the atoms to Rydberg states that are 10${}^{8}$ times more polarizable than the ground state. We attribute the measured fields to charging of the insulators between the atom chip wires. Surprisingly, it is found that although the chip wire currents were turned off before Rydberg excitation, the measured fields were strongly influenced by how the wire currents had been applied. These fields may be dramatically lowered with appropriate voltage biasing, suggesting configurations for the future development of hybrid quantum systems.

J. D. Carter, J. D. D. Martin

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 ($\ensuremath{\kappa}\ensuremath{\approx}1$).

James P. Shaffer

F. B. Dunning

D. Davtyan, Shimon Machluf, Maarten L. Soudijn +4 more

Experiments handling Rydberg atoms near surfaces must necessarily deal with the high sensitivity of Rydberg atoms to (stray) electric fields that typically emanate from adsorbates on the surface. We demonstrate a method to modify and reduce the stray electric field by changing the adsorbate distribution. We use one of the Rydberg excitation lasers to locally affect the adsorbed dipole distribution. By adjusting the averaged exposure time we change the strength (with the minimal value less than $0.2\phantom{\rule{0.28em}{0ex}}\mathrm{V}/\mathrm{cm}$ at $78\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$ from the chip) and even the sign of the perpendicular field component. This technique is a useful tool for experiments handling Rydberg atoms near surfaces, including atom chips.