Enhanced 2-µm and upconversion luminescence properties regulated by network structure in Ho³⁺/Yb³⁺ co-doped germanate...

Rare-earth (RE) ions doped laser glass has attracted the interest of many researchers because of its numerous potential applications in planar waveguides and fiber lasers. In this work, the 2-µm and upconversion luminescence properties of Ho³⁺ are simultaneously enhanced through the design of components used to regulate the network structure of the germanate glass. Furthermore, the thermal, structural, and spectroscopic properties of the Ho³⁺/Yb³⁺ co-doped germanate laser glass are systematically investigated. It is noted that the calculated gain coefficient of the Nb₂O₅ modified germanate laser glass can reach as high as 3.05 cm^-1 at 2047 nm. These results suggest that the prepared germanate laser glass with superior performances is a promising candidate for 2-µm mid-infrared laser materials applications.