Preparation and characterization of transparent Tm:YAG ceramics

Polycrystalline (Y3−xTmx)Al5O12 (x = 0, 0.18, 0.9, 1.5, 3) ceramics were fabricated by a solid-state reaction method using high-purity micrometer-sized powders. Tm-doped ceramics with an almost perfect pore-free structure and high transparency were obtained by advanced ceramic processing. The average grain size and grain boundary width were 15 μm and 1 nm, respectively. The Y2.82Tm0.18Al5O12 (6 at.% Tm:YAG) ceramic slab (5 mm × 5 mm × 3.5 mm) was end-pumped by a Ti:sapphire laser at 785 nm and the maximum output power of 725 mW was obtained with a slope efficiency of 36.2% at 2012 nm.