Miniature Biplanar Coils for Alkali-Metal-Vapor Magnetometry

Atomic spin sensors offer precision measurements using compact microfabricated packages, placing them in a competitive position for both market and research applications. The performance of these sensors, such as the dynamic range, may be enhanced through magnetic field control. In this work, we discuss design miniature coils three-dimensional localized control by direct placement around sensor, flexible alternative to global approaches used previously. Coils are designed on biplanar surfaces stream-function approach then fabricated standard printed-circuit techniques. Application laboratory-scale optically pumped magnetometer sensitivity approximately $20\phantom{\rule{0.2em}{0ex}}\mathrm{fT}/\sqrt{\mathrm{Hz}}$ is shown. We also demonstrate coil set measuring $7\ifmmode\times\else\texttimes\fi{}17\ifmmode\times\else\texttimes\fi{}17\phantom{\rule{0.2em}{0ex}}{\mathrm{mm}}^{3}$ that optimized specifically magnetoencephalography, where multiple operated close proximity one another. Characterization profile ${}^{87}$$\mathrm{Rb}$ free-induction spectroscopy other techniques show $>96\mathrm{%}$ homogeneity over target volume MEMS vapor cell stray-field contour $1\mathrm{%}$ at 20 mm from center cell.