Spectroscopic properties of Yb3+-doped fluorophosphate glasses with low phosphate content

Abstract

A series of new fluorophosphate glasses of 5Ba(PO3)2–10BaF2–18.5CaF2–10MgF2–18.5SrF2–(38–x)AlF3–xYbF3 (x = 0.5, 1, 2, 5, 8, 10) composition was synthesized. Experimental characterization, including absorption, luminescence, and luminescence kinetics measurements, was performed. Based on experimental data, the optimal concentration of Yb3+ ions, providing the highest gain, was established. To characterize potential laser performance of the studied glasses several parameters, including pump saturation, minimal pump intensity, and minimal fraction of excited ions needed to balance gain and absorption, were calculated. Dependence of gain cross section on the excited state population was determined to characterize amplifying properties of the glasses.