Light shift averaging in paraffin-coated alkali vapor cells

TL;DR

This paper shows that in paraffin-coated alkali vapor cells, the long coherence times cause spatial averaging of light shifts, making the averaged shift independent of light intensity distribution, which can improve magnetometer stability.

Contribution

The study introduces the concept of light shift averaging in paraffin-coated cells, revealing a mechanism that reduces systematic errors in optically pumped magnetometers.

Findings

Light shifts are spatially averaged over the cell volume.

Averaged light shift becomes independent of light intensity distribution.

Results can be extended to other phenomena in coated cells.

Abstract

Light shifts are an important source of noise and systematics in optically pumped magnetometers. We demonstrate that the long spin coherence time in paraffin-coated cells leads to spatial averaging of the light shifts over the entire cell volume. This renders the averaged light shift independent, under certain approximations, of the light-intensity distribution within the sensor cell. These results and the underlying mechanism can be extended to other spatially varying phenomena in anti-relaxation-coated cells with long coherence times.