Cavity-enhanced Ramsey spectroscopy at a Rydberg-atom-superconducting-circuit interface

Abstract

The coherent interaction of Rydberg helium atoms with microwave fields in a $\lambda /4$ superconducting coplanar waveguide resonator has been exploited to probe the spectral characteristics of an individual resonator mode. This was achieved by preparing the atoms in the 1s55s${}^3$S${}_1$ Rydberg level by resonance enhanced two-color two-photon excitation from the metastable 1s2s${}^3$S${}_1$ level. The atoms then travelled over the resonator in which the third harmonic microwave field, at a frequency of ${\omega }_{\mathrm{res}}=2\pi \times 19.556$ GHz, drove the two-photon 1s55s${}^3$S${}_1\to$1s56s${}^3$S${}_1$ transition. By injecting a sequence of Ramsey pulses into the resonator, and monitoring the coherent evolution of the Rydberg state population by state-selective pulsed electric field ionization as the frequency of the microwave field was tuned, spectra were recorded that allowed the resonator resonance frequency and quality factor to be determined with the atoms acting as microscopic quantum sensors.

5 pages, 4 figures

References in corpus (7)

• Quantum technologies with hybrid systems
• Efficient and robust analysis of complex scattering data under noise in microwave resonators
• Microwave-to-optical frequency conversion using a cesium atom coupled to a superconducting resonator
• Detrimental adsorbate fields in experiments with cold Rydberg gases near surfaces
• Microwave to optical conversion with atoms on a superconducting chip
• Rydberg atoms with a reduced sensitivity to dc and low-frequency electric fields
• Reducing the sensitivity of Rydberg atoms to dc electric fields using two-frequency ac field dressing