Broadband optical amplification in silicate glass-ceramic containing beta-Ga2O3 : Ni2+ nanocrystals

We demonstrate broadband optical amplification at 1.3 mu m in silicate glass-ceramics containing beta-Ga2O3:Ni2+ nanocrystals with 980 nm excitation for the first time. The optical gain efficiency is calculated to be about 0.283 cm(-1) when the excitation power is 1.12 W. The optical gain shows similar wavelength dependence to luminescence properties. (C) 2007 Optical Society of America.

Diode-pumped passively q-switched Nd : YAG ceramic laser with a Cr4+: YAG crystal-satiable absorber

Transparent polycrystalline Nd:YAG ceramics were fabricated by solid-state reactive sintering a mixture of commercial Al2O3,Y2O3, and Nd2O3 powders. The powders were mixed in ethanol and doped with 0.5 wt% tetraethoxysilane, dried, and pressed. Pressed samples were sintered at 1750 degrees C in vacuum. Transparent fully dense samples with average grain sizes of 10 mu m were obtained. The 1 at.% Nd:YAG ceramic was used to research passively Q-switched laser output with a Cr4+:YAG crystal as a saturable absorber. An average output power of 94 mW with a pulse width of 50 ns was obtained when the incident pump power was 750 mW. The slope efficiency was 13%. The pulse energy is 5 mu J, and the peak power is about 100 W.

Diode-pumped Yb : YAG ceramic laser

Transparent polycrystalline Yb:YAG ceramics were fabricated by solid-state reactive sintering a mixture of commercial Al2O3, Y2O3, and Yb2O3 powders. The powders were mixed in ethanol and doped with 0.5 wt% tetraethoxysilane, dried, and pressed. Pressed samples were sintered at 1730 degrees C in vacuum. Transparent fully dense samples with grain sizes of several micrometers were obtained. The phase from 1500 degrees to 1700 degrees C was important for the grain growth, in which the grains grew quickly and a mass of pores were eliminated from the body of the sample. Annealing was an important step to remove the vacancies of oxygen and transform Yb2+ to Yb3+. The 1 at.% Yb:YAG ceramic sample was pumped by a diode laser to study the laser properties. The maximum output power of 1.02 W was obtained with a slope efficiency of 25% at 1030 nm. The size of the lasering sample was 4 mm x 4 mm x 3 mm.

Synthesis of CaCu3Ti4O12 ceramic via a sol-gel method

The novel nano-ultrafine powders for the preparation of CaCu3Ti4O12 ceramic were prepared by the sol-gel method and citrate auto-ignition method. The obtained precursor powders were pressed, sintered at 1000 degrees C to fabricate microcrystal CaCu3Ti4O12 ceramic. The microcrystalline phase of CaCu3Ti4O12 was confirmed by X-ray powder diffraction (XRD). The morphology and size of the grains of the powders and ceramics under different heat treatments were observed using scanning electron microscopy (SEM). The relative dielectric constant of the ceramic sintered at 1000 degrees C was measured with a magnitude of more than 10(4) at room temperature, which was approaching to those of Pb-containing complex perovskite ceramics, and the loss tangent was less than 0.20 in a broad frequency region. The relative dielectric constant and loss tangent were also compared with that of CaCu3Ti4O12 ceramic prepared by other reported methods. (c) 2006 Elsevier B.V. All rights reserved.

Investigation of the spectroscopic properties of Yb3+-doped yttrium lanthanum oxide transparent ceramic

Spectroscopic properties of (Y0.9-xLa0.1Ybx)(2)O-3 transparent ceramic were studied. Two main absorption peaks of the specimen are centered at 940 and 970 nm, which are suitable for InGaAs laser diode pumping. The main emission peaks were located at 1032 and 1075 nm with larger emission cross-section and longer fluorescence lifetime than those of Yb:Y2O3. These properties of (Y0.9-xLa0.1Ybx)(2)O-3 transparent ceramic are favorable to achieve high efficiency and high power laser output. (c) 2007 Elsevier B.V. All rights reserved.

Cooperative up-conversion luminescence of ytterbium doped yttrium lanthanum oxide transparent ceramic

The up-conversion luminescence of Yb3+-doped yttriurn lanthanum oxide transparent ceramic was investigated. It was ascribed to cooperative luminescence originated from the coupled states of the Yb3+ ion pairs. The proper doping of La2O3 can remove the cooperative luminescence of Yb3+ ion. But excessive La2O3 (at least 10 at.%) the cooperative up-conversion of Yb3+:Y2O3 is obtained again, and the intensity of up-conversion luminescence strengthens with the increase of La2O3 content. (c) 2007 Elsevier B.V. All rights reserved.

Diode-end-pumped passively mode-locked ceramic Nd : YAG Laser with a semiconductor saturable mirror

We report on a diode- pumped CW passively mode locked ceramic Nd: YAG laser with SESAM ( semiconductor saturable absorber mirror), wavelength 1064nm. At a pump power of 7.6w, the pulse width was estimated to be similar to 8.3ps with repetition rate similar to 130MHz and the average output power was 1.59w. To our knowledge, this was the first demonstration that ceramic Nd: YAG was used for diode pumped CW passively mode locking. (C) 2005 Optical Society of America.