Magneto-Optics Features of Radiation Transitions of Non-Kramers Tm3+ Ion in Yttrium-Aluminum Garnet Crystals

The spectra of luminescence and magnetic circular polarization of a single crystal of thulium-yttrium garnet-aluminate Tm3+:YAG have been studied within the visible spectral range at a temperature of 90 and 300 K in a magnetic field of 10 kOe. Based on the analysis of optical and magneto-optical data, the presence of "quasi-degenerate" states of excited multiplets 1D2, 3F4,3G4 and the ground multiplet 3H6 of the Tm3+ RE ion in garnet-aluminate YAG at the radiative transitions 1G4→3H6, 1D2→3F4 and 1D2→3F3 has been determined. The effect of quantum mechanical “mixing” plays a significant role in the occurrence of magneto-optical effects on luminescence bands caused by “forbidden” 4f→4f transitions in the non-Kramers Tm3+ ion having a “quasi-doublet” structure in the energy spectra.