Optical detection of magnetic resonance of FAand F centres in CaO:Mg

Abstract

Optically detected magnetic resonance experiments on F and F_A(Mg) centres in irradiated CaO:Mg crystals show that the sign and magnitude of the resonance signals are consistent with T₁>or approximately= tau _A for both defects. This means that resonance always occurs as an increase in the intensity of circularly polarised light. The wavelength dependence of these resonances is shown to have important consequences for the selective feeding of the excited-state spin triplet configurations. The data are consistent both with the polarised luminescence studies and the photoconversion of F centres and conversion of F_A⁺ centres to F_A centres reported by Welch and Hughes (1980).