Laser spectroscopy was used to investigate the effect of MgO or ZnO co-doping upon the Nd3+ centers which formed in this material. Both co-dopant oxides produced the same effect, so 2 new Nd3+ centers appeared in both sets of doped crystals. The new centers corresponded to a small percentage (less than 1%) of Nd3+ which were displaced from Li+ sites to a new lattice site.

E.Camarillo, J.Hernández, J.Garcia-Solé, U.Caldiño, J.E.M.Santiuste, H.Loro, M.Voda, F.Jaque, H.Murrieta: Journal of Physics - Condensed Matter, 1995, 7[49], 9635-41