Fabrication of transparent Yb,Cr:YAG ceramics by a solid-state reaction method

Transparent ytterbium and chromium codoped yttrium aluminum garnet (Yb,Cr:YAG) ceramics, containing Ca as charge counter element and TEOS as sintering aid, were fabricated by a solid-state reaction method using high-purity Y2O3, Al2O3, Cr2O3 and Yb2O3 powders as raw materials. The mixed powder compacts were sintered at 1770 °C for 10 h under vacuum and annealed at 1450 °C for 20 h in air. The Yb,Cr:YAG ceramics exhibit a pore free structure with an average grain size of about 40 μm. The optical transmittance of 5 at% Yb, 0.025 at% Cr:YAG reaches 75% at 1100 nm. The strong absorptions of Yb3+ at 940 and 968 nm are suitable for InGaAs diode laser pumping; an absorption band at 1030 nm is suitable for passive Q-switch laser output at 1030 nm. Transparent Yb,Cr:YAG ceramics may be a potential material for compact, efficient, high-stability diode-laser-pumped passive Q-switched solid-state lasers.