Transparent nano-glass-ceramics for efficient infrared emission

Abstract

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 Ho 3+ , Dy 3+ , Eu 3+ , Tm 3+ , Er 3+ , dissolve in the cubic β-PbF 2 nano-crystals with a certain diameter of the order of 10 nm, 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 β-PbF 2 (at about 250 cm −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.