ELECTRON-PARAMAGNETIC-RESONANCE AND FLUORESCENCE-LINE-NARROWING MEASUREMENTS OF THE LASING CENTER IN CR-DOPED FORSTERITE

We present results of EPR and near-infrared fluorescence-line-narrowing experiments performed on Cr-doped forsterite. The optical measurements permit identification of the signals in the complex EPR spectrum due to the near-infrared lasing center. The site symmetry of the lasing center is shown to be c(s) with the mirror plane being in the crystallographic ab plane. The magnetic z axes of the two magnetically inequivalent sites are in the mirror plane at an angle of +/- 43-degrees to the b axis. In addition, the relative energies of the ground-state triplet have also been measured and can be written in terms of spin Hamiltonian energy parameters: D = +2.20 and E = -0.149 cm-1.