Emission and excitation spectra, and luminescence decay curves, of Ni- and Cr-doped enstatite single crystals were measured at temperatures down to 10K. In all of the crystals, an emission band which peaked at about 1520nm was attributed to the 3T2 → 3A2 transition of octahedral Ni2+ centres, while a luminescence at about 800nm was attributed to the 4T2 → 4A2 transition of octahedral Cr3+ centres. Chemical analysis confirmed the presence of Ni impurities in nominally Cr-doped crystals, and of Cr impurities in nominally Ni-doped crystals. The peak stimulated emission cross-section of the 1520nm emission of Ni2+ was 3 x 10-20cm2.

Luminescence of Ni2+ and Cr3+ Centres in MgSiO3 Enstatite Crystals. R.Moncorgé, M.Bettinelli, Y.Guyot, E.Cavalli, J.A.Capobianco, S.Girard: Journal of Physics - Condensed Matter, 1999, 11[35], 6831-41