Dressed state EPR nutations of E1′ centers in neutron-irradiated quartz

Dressed state electron paramagnetic resonance (EPR) nutations of E1′ centers in neutron-irradiated crystalline quartz are observed using, in addition to the continuous microwave field 2B1cos(ωt) and the pulse of longitudinal magnetic field, a linearly polarized RF field 2B2cos(ωrft) along the static magnetic field. The dressed nutation of the frequency ω2=γB2 is detected when the RF field frequency, ωrf, is near the frequency of bare spin nutation ω1=γB1 (γ is the electron gyromagnetic ratio). Our results give evidence for the line-narrowing effect associated with the dressed nutation and the amplitude asymmetry of the left (ω1−ω2) and right (ω1+ω2) components in Fourier spectra of observed nutation signals.