  We report a new technique for generating magnetic resonance with synchronous
modulation of two-photon resonant light fields. Magnetic resonances in
fluorescence from a sodium cell are measured to demonstrate suitability of this
technique for remote magnetometry. A strong magnetic resonance with its dip
corresponding to the Larmor frequency is produced in the presence of a
transverse magnetic field. An additional resonance at 3\{Omega_L} is observed,
which can be used to determine the magnetic field orientation. We have
developed a theoretical model based on the density matrix equations to verify
our experimental observations. An average magnetic field sensitivity of 41
\mathbf{pT}/\sqrt{\mathbf{Hz}} is measured using light duty cycles ranging from
35% to 10%. We have discussed possible changes that can be made to improve the
sensitivity of this scheme further.
