Preparation and upconversion luminescence of Y3Al5O12 : Yb3+, Er3+ transparent ceramics

YAG: 1% (atom fraction) Yb3+, 0.5% (atom fraction) Er3+ transparent ceramics were fabricated by the solid state reaction method using high-purity Y2O3, Al2O3, Yb2O3, and Er2O3 powders as starting materials. The mixed powder compact was sintered at 1760 degrees C for 6 h in vacuum and annealed at 1500 degrees C for 10 h in an air atmosphere. The ceramics consisted of about 10 mu m grains and exhibited a pore-free structure. The optical transmittance of the ceramics at 1064 nm was nearly 80%. Upconversion emissions were investigated on the ceramics pumped by a 980 nm continuous wave diode laser, and strong green emission centered at 523 and 559 nm and red emission centered at 669 nm were observed, which originated from the radiative transitions of H-2(11/2) -> I-4(15/2) S-4(3/2) -> I-4(15/2), and F-4(9/2) -> I-4(15/2) of Er3+, ions, respectively.