Detrimental adsorbate fields in experiments with cold Rydberg gases near surfaces

TL;DR

This study investigates how adsorbate-induced electric fields near surfaces affect Rydberg atom experiments, revealing significant field increases that limit the feasibility of cavity QED applications on atom chips.

Contribution

It provides the first detailed measurement of adsorbate-induced electric fields near surfaces in Rydberg atom experiments, highlighting their impact on experimental limitations.

Findings

Electric fields increase near surfaces with atom deposition.

Fields reach up to 1 V/cm at 30 μm after hundreds of clouds.

Adsorbate fields pose challenges for cavity QED experiments.

Abstract

We observe the shift of Rydberg levels of rubidium close to a copper surface when atomic clouds are repeatedly deposited on it. We measure transition frequencies of rubidium to S and D Rydberg states with principal quantum numbers n between 31 and 48 using the technique of electromagnetically induced transparency. The spectroscopic measurement shows a strong increase of electric fields towards the surface that evolves with the deposition of atoms. Starting with a clean surface, we measure the evolution of electrostatic fields in the range between 30 and 300 \mum from the surface. We find that after the deposition of a few hundred atomic clouds, each containing ~10^6 atoms, the field of adsorbates reaches 1 V/cm for a distance of 30 \mum from the surface. This evolution of the electrostatic field sets serious limitations on cavity QED experiments proposed for Rydberg atoms on atom chips.