Largest enhancement of broadband near-infrared emission of Ni2+ in transparent nano-glass ceramics: using Nd3+ as sensitizer and Yb3+ as energy transfer bridge

An ultrabroadband near-infrared (NIR) emission of Ni2+ is demonstrated in a highly transparent nano-glass ceramic (nano-GC) containing Ga2O3 nanocrystals with 808 nm excitation of Nd3+. It is also shown that by adding Yb3+ as an energy transfer (ET) bridge, the Ni2+ emission could be substantially enhanced. The dopant distribution was studied using advanced analytical transmission electron microscopy. This, together with optical transmission measurements, steady-state and time-resolved emission spectra, is utilized to understand the underlying ET mechanisms between Nd3+, Yb3+, and Ni2+. The feasibility of this device as a viable source is demonstrated using dual-laser pumping at 808 and 980 nm for the greatest Ni2+ emission enhancement reported to date. The Nd3+/Yb3+/Ni2+ triply doped nano-GC offers a promising gain medium for broadband and tunable NIR fiber amplifiers.