Systematic nonuniform field effects in miniature atomic co-magnetometers

Wafer-fabricated vapor cells are essential components in the development of scalable, field-deployable atomic sensing systems, including atomic spin gyroscopes. This paper presents a systematic study of magnetic resonance spectra obtained in a two-chamber, millimetre-sized, wafer-fabricated cell containing Cs, 129 Xe, 131 Xe, and N 2 buffer gas. For a range of vapor temperatures and pump powers, we identify characteristic structural and dynamical effects, including electric quadrupole splitting of the 131 Xe frequency and spectral branching of the 129 Xe frequency and linewidth as the signature of a Parity-Time (PT) symmetry-broken phase. Remarkably, we demonstrate that a primary class of systematic nonuniform field effects can be reduced to a simple one-dimensional linear gradient. We leverage these effects to offer regimes of optimised and robust sensor operation, setting a benchmark for the performance of wafer-fabricated vapor cells in both atomic spin gyroscopes and more broad quantum technologies.