  Sensitive magnetometers have been applied in a wide range of research fields,
including geophysical exploration, bio-magnetic field detection, ultralow-field
nuclear magnetic resonance, etc. Commonly, magnetometers are directly placed at
the position where the magnetic field is to be measured. However, in some
situations, for example in near space or harsh environments, near nuclear
reactors or particle accelerators, it is hard to place a magnetometer directly
there. If the magnetic field can be detected remotely, i.e., via stand-off
detection, this problem can be solved. As optical magnetometers are based on
optical readout, they are naturally promising for stand-off detection. We
review various approaches to optical stand-off magnetometry proposed and
developed over the years, culminating in recent results on measuring magnetic
fields in the mesosphere using laser guide stars, magnetometry with
mirrorless-lasing readout, and proposals for satellite-assisted interrogation
of atmospheric sodium.
