  We report the manipulation of nitrogen vacancy (NV) spins in diamond when
nearby ferrimagnetic insulator, yttrium iron garnet, is driven into precession.
The change in NV spin polarization, as measured by changes in
photoluminescence, is comparable in magnitude to that from conventional
optically detected magnetic resonance, but relies on a distinct mechanism as it
occurs at a microwave frequency far removed from the magnetic resonance
frequency of the NV spin. This observation presents a new approach to
transferring ferromagnetic spin information into a paramagnet and then
transducing the response into a robust optical signal. It also opens new
avenues for studying ferromagnetism and spin transport at the nanoscale.
