Crystal growth and spectroscopic characterization of Yb-doped and Yb, Na-codoped PbF2 laser crystals

High-quality pure PbF2, Yb:PbF2 and Yb, Na:PbF2 crystals are grown by the Bridgman method in a nonvacuum atmosphere. Room-temperature absorption, photoluminescence spectra, and fluorescence lifetimes belonging to the transitions between ground state 2F7/2 and the excited state 2F5/2 of Yb3+ ions in these crystals have been investigated. The influence of codoping with Na+ ions on the spectra has been studied. Experimental results show that codoping Na+ ions in different Na:Yb ratios can modulate the spectroscopy and photoluminescence properties of Yb3+ ions in a PbF2 lattice in a large scope: the Na+ ions codoping with Yb3+ as charge compensators can suppress the deoxidization of Yb3+ to Yb2+, enhance the luminescence intensity and lengthen luminescence lifetime of Yb3+ ions.

► Bridgman-grown Yb: PbF2 and Yb, Na: PbF2 laser crystals have been investigated for their absorption, emission spectra and luminescence lifetime.
► The influence of codoping with Na+ ions on the spectra has been studied.
► The results indicate that The Yb2+ ions are unavoidable in Yb: PbF2 crystal, and the presence of the Na+ ions drastically decreases the absorption intensity of the characteristic UV peaks of Yb2+ ions, enhances the emission intensity, broadens the emission bands and lengthen luminescence lifetime of Yb3+ ions.