Measuring short range stray electric fields with a force quantum sensor

We use a quantum sensor based on trapped atom interferometry, and designed for probing short range atom-surface interactions, to characterize parasitic electric fields produced by adsorbed atoms or surface charges on a dielectric mirror. Applying controlled external fields with in-situ electrodes allows measuring electric field gradients with a relative uncertainty of order of 1% via variations of the force induced onto the atoms. More, our sensor can also be configured as a trapped microwave clock, allowing for direct measurements of the electric field amplitude via the Stark shift of the hyperfine transition frequency. Such measurements of the electric field amplitudes and gradients as a function of the atom-surface distance can be used to construct a model for the spatial distribution of the atoms adsorbed onto the surface of the mirror, and to accurately correct local force measurements, such as related to the Casimir–Polder interaction, from the detrimental impact of adsorbed atoms or stray charges.