  Optically pumped atomic magnetometers (OPMs) offer highly sensitive magnetic
measurements using compact hardware, offering new possibilities for practical
precision sensors. Double-resonance OPM operation is well suited to unshielded
magnetometry, due to high sensor dynamic range. However, sensor response is
highly anisotropic with variation in the orientation of the magnetic field. We
present data quantifying these effects and discuss implications for the design
of practical sensors.
