T. Uematsu

72 W Nd:Y3Al5O12 ceramic laser

A high-power continuous-wave polycrystalline 1% Nd:Y{sub 3}Al{sub 5}O{sub 12} (Nd:YAG) ceramic rod laser was demonstrated. With 290 W/808 nm laser diode pumping, cw laser output of 72 W was obtained at 1064 nm. The optical-to-optical conversion efficiency is 24.8%. Thermally induced birefringence properties of Nd:YAG ceramic was also investigated. {copyright} 2001 American Institute of Physics.A high-power continuous-wave polycrystalline 1% Nd:Y3Al5O12 (Nd:YAG) ceramic rod laser was demonstrated. With 290 W/808 nm laser diode pumping, cw laser output of 72 W was obtained at 1064 nm. The optical-to-optical conversion efficiency is 24.8%. Thermally induced birefringence properties of Nd:YAG ceramic was also investigated.

Nd3+:Y2O3 Ceramic Laser

We have demonstrated CW one-micron laser oscillation in new ceramic laser material on the base of cubic Nd3+:Y2O3. Slope efficiency of 32% was achieved on an uncoated 1.5 at.% Nd3+:Y2O3 ceramic plate with size of 14 ×2.7 mm under laser diode end-pumping.

Promising ceramic laser material: Highly transparent Nd3+:Lu2O3 ceramic

A solid-state laser material based on highly transparent cubic Nd3+:Lu2O3 ceramic was developed using nanocrystalline technology and a nonpress vacuum sintering method. Spectroscopic properties of this ceramic laser material were investigated. At room temperature under single-laser diode pumping, efficient continuous wave laser oscillation was demonstrated at two wavelengths of the 4F3/2→4I11/2 channel. The potential application of such a laser material was also discussed.

Yb3+:Y2O3 Ceramics – a Novel Solid-State Laser Material

A new solid-state laser based on Yb3+-doped highly transparent nanocrystalline yttria (Y2O3) ceramics was developed. At room temperature and under a pump power of 2.63 W from a single InGaAs laser diode at ≈ 0.94 µm, a continuous-wave laser output of 0.47 W at 1.077 µm wavelength was obtained corresponding to a slope efficiency of about 32%. Some main spectroscopic properties of Yb3+:Y2O3 ceramics were also investigated.

Yb3+:Sc2O3 ceramic laser

A solid-state laser material based on highly transparent Yb3+-doped scandia (Sc2O3) ceramic was developed using nanocrystalline technology and the nonpress vacuum sintering method. Continuous wave laser oscillations were obtained at around 1041 and 1094 nm using a 2.5 at. % Yb3+:Sc2O3 ceramic plate. Broadband lasing spectra were observed.

36-W diode-pumped continuous-wave 1319-nm Nd:YAG ceramic laser

Continuous-wave output at 1319 nm was obtained from a laser-diode-pumped 1% ceramic Nd:YAG laser. As much as 36.3-W output was obtained under pump power of 290 W, with an optical-to-optical conversion efficiency of 12.5%.

New data on the physical properties of Y3Al5O12-based nanocrystalline laser ceramics

Microhardness and fracture toughness of highly transparent Y3Al5O12-and Y3Al5O12: Nd3+-based nanocrystalline ceramics are measured for the first time. For the Y3Al5O12: Nd3+ laser ceramics, the use of a longitudinal scheme with a diode-laser pumping at a wavelength of 1.3186 mm (4F3/2 → 4I13/2 channel) enabled one to attain an output power of continuous-wave lasing of ∼3.7 W with 35% efficiency.

Chromium Doped Y3Al5O12 Ceramics – a Novel Saturable Absorber for Passively Self-Q-Switched One-Micron Solid State Lasers

We demonstrated a laser-diode pumped all ceramic passively self-Q-switched laser with Cr4+:Y3Al5O12 ceramics as a saturable absorber and Nd3+:Y3Al5O12 ceramics as a gain medium. A 190-W peak power was obtained with a 20-ns pulse duration and a 12-kHz repetition rate at ≈ 900-mW pumping power. The result indicates that Cr4+:Y3Al5O12 single crystals can be replaced with more productive and cheaper Cr4+:Y3Al5O12 ceramics for many practical solid-state one-micron lasers.

Refractive indices of laser nanocrystalline ceramics based on Y3Al5O12

Refractive indices of the nanocrystalline Y3Al5O12 ceramic and a garnet single crystal of the same composition have been measured. In the visible and near IR range (0.4–1.064 μm), the prism method was used; in the medium IR range (2–6.2 μm), the interference method with the use of thin plates was applied. The refractive indices of these crystalline materials are practically the same over the entire spectral range studied and are described by the approximate formula proposed earlier for a single crystal. The parameters of the continuos-wave lasing in the nanocrystalline Y3Al5O12 ceramic doped with Nd3+ and Yb3+ ions measured recently are presented.

Development of Nd:YAG ceramic lasers

Highly transparent Nd:YAG ceramics were fabricated using vacuum sintering method where the raw powder was prepared by nanocrystalline technology. Optical properties were investigated and compared with those of YAG single crystals, almost identical results were obtained. The thermal conductivity of Nd: YAG ceramic was measured and the result was similar to that of Nd:YAG single crystal. End-pumped Nd:YAG ceramic laser were developed. Slope efficiencies of 61% and 58% were obtained for 1% and 2% Nd:YAG ceramic lasers. Just recently, high power 1.46 kW Nd:YAG ceramic laser was developed with an optical-to-optical efficiency of 42%.