Transparent nano-glass-ceramics for efficient infrared emission

We summarise the experimental data and provide a general theoretical basis for efficient infrared emission in the rare-earth doped transparent oxyfluoride nano-glass-ceramics. In these glass-ceramics, more than 90% fraction of the rare-earth dopant, such as Ho3+, Dy3+, Eu3+, Tm3+, Er3+, dissolve in the cubic beta-PbF2, nano-crystals with a certain diameter of the order of 10nm, whilst these nano-crystals are embedded in a robust aluminosilicate glass network. A remarkably low maximal phonon energy coupled to the rare-earth dopant in the beta-PbF2 (at about 250cm(-1)) permits the efficient infrared emission of the dopants from the levels, which are non-radiatively quenched in other glassy hosts. Further advantage of this nano-glass-ceramic material is in its robustness typical of the aluminosilicate glass, which offers fabrication of durable waveguide devices. The site of the rare-earth dopant is proposed to be nearly cubic with 8 fluorine ligands around the dopant resulting in prolonged lifetimes of the lasing levels and admixture of the vibronic coupling to the strength of some electric dipole transitions. (c) 2007 Elsevier B.V. All rights reserved.