The magnetization of ruby in a magnetic field at 300\ifmmode^\circ\else\textdegree\fi{}K is changed when the ruby is optically pumped with linearly polarized radiation from a
Q-switched ruby laser. With a magnetic field parallel to the trigonal axis, laser light polarized parallel to this axis induces transitions from the spin \ifmmode\pm\else\textpm\fi{}\textonehalf{} levels of the
4A2 ground state to the levels of the
E(2E) excited state. The change in
Mz is linearly proportional to
H except near the anticrossing points of the
4A2 spin levels at 2.07 and 4.14 kG. At these field strengths, there is an enhancement of the magnetization caused by state mixing of the
4A2 wave functions. When
H has a small component perpendicular to the
z axis, a magnetization is detected parallel to this component in the vicinity of 4.14 kG. The effect requires a long ground-state relaxation time. In a separate experiment, the relaxation of
Mz was found to vary from 0.13 \ensuremath{\mu}sec in zero magnetic field to a constant value of 0.57 \ensuremath{\mu}sec for fields above 60 G.
The method of transferring the frequency of an optically detected magnetic resonance both up and down by an arbitrary value is implemented in a single-beam optical pumping scheme by modulating the linearly polarized beam component. The possibility of observing the Hanle resonance in a magnetic field virtually zeroed upon transition to a rotating coordinate system is demonstrated. A model experiment was carried out, confirming the fundamental feasibility and effectiveness of the method. Keywords: Optically detectable magnetic resonance, optical resonance frequency transfer, Hanle effect, Bell-Bloom scheme, quantum magnetometer.