Upconversion luminescence of high content Er-doped YAG transparent ceramics

The various high content Er-doped YAG transparent ceramics with excellent transparency up to nearly 84% at the visible band and the near-infrared band were prepared by the solid-state reaction and the vacuum sintering technique. It is found that the samples exhibit pore-free structures and there are no secondary phases both at the grain boundaries and the inner grains. The average grain size of the Er:YAG ceramics is about 30 μm. The green and red upconversion luminescences in the Er:YAG ceramics pumped by a 980 nm LD were observed. The different upconversion mechanisms depending on Er content in the Er:YAG ceramics and the LD power were also discussed.