Magnetic resonance signals from the optically oriented two-level spin system in the presence of nonresonant fields

A theoretical and experimental investigation into the motion of the magnetization vector in the presence of two additional circularly-polarized nonresonant rf fields, when these fields rotate in the plane analogous to that of resonant rf fields with the frequency $\omega$, has been performed. The nonresonant fields are equal in magnitude; their frequencies differ from the resonant frequency $\omega$ by the value of $\pm\Omega$, which essentially exceeds the magnetic resonance line width.