Neodymium doped yttrium aluminum garnet (Y3Al5O12) nanocrystalline ceramics—a new generation of solid state laser and optical materials

The design and operation of solid-state Raman lasers

After a brief examination of known insulating laser crystals and the stimulated emission channels of their generating activator ions, this article reviews recent advances in the development of novel lasing crystals and ceramics, as well as inorganic and organic nonlinear-laser crystals for χ(3) and cascaded χ(3) ↔ χ(2) frequency converters Several new modern attractive technologies in the physics and techniques of crystalline lasers are also discussed

https://onlinelibrary.wiley.com/doi/pdf/10.1002/lpor.200710008

Laser crystals and ceramics: recent advances

▪ Abstract Yttrium aluminum garnet (YAG) (Y3Al5O12) single crystals doped with active species such as Nd and Yb have been used as laser media in solid-state lasers requiring high energy and excellent beam quality. This is because single crystals have extremely high thermal mechanical properties and optical qualities and because they enable high-efficiency laser oscillation. In 1995 the authors, using polycrystalline Nd:YAG, demonstrated a high-efficiency laser that was comparable to a single-crystal laser. Subsequently, single-longitudinal-mode oscillation, green and blue laser oscillation, and ultrashort-pulse laser oscillation were reported. Using the ceramic powder approach, the authors developed a composite laser element with a complicated structure that could not be produced by crystal growth techniques. This review discusses problems of conventional single-crystal growth, the fabrication and characteristics of ceramic lasers, laser oscillation properties (continuous-wave and pulse operation), light-...

Progress in ceramic lasers

This paper reports recent progress in the production of polycrystalline Nd:YAG (Y 3 Al 5 O 12 ), Nd:YSAG (Y 3 Sc 1.0 Al 4.0 O 12 ), Yb:YSAG ceramics, and a Nd-doped YAG single crystal with an almost perfect pore-free structure by advanced ceramic processing. The laser conversion efficiency of pore-free polycrystalline Nd- and Yb-doped ceramics is extremely high, and their optical qualities are comparable with that of commercial high-quality Nd:YAG single crystals. We have also succeeded in the fabrication of a Nd:YAG single crystal, which can be used for laser oscillation, by the solid-state reaction method. Laser oscillation efficiency was very low when the pores remained inside the single crystal; however, the laser oscillation efficiency of the pore-free Nd:YAG single crystal was slightly higher than that of polycrystalline Nd:YAG ceramics having high optical quality. From this fact, it was recognized that optical scattering occurs mainly in the residual pores inside the Nd:YAG ceramics and the scattering at the grain boundary is very less. In addition, we confirmed that a heavily doped Nd:YAG single crystal can be fabricated by the sintering method. Moreover, we have demonstrated the fabrication of a composite ceramic with complicated structures without the need for precise polishing and diffusion bonding. Advanced ceramic processing, which enables design flexibility of the laser element, presented in this work is important in the development of a high-performance laser (high efficiency, high beam quality, and high output energy, etc.).

Synthesis and Performance of Advanced Ceramic Lasers

Tetragonal vanadates YVO4 and GdVO4 – new efficient χ(3)-materials for Raman lasers

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.

https://iopscience.iop.org/article/10.1143/JJAP.40.L1277/pdf

Nd3+:Y2O3 Ceramic Laser

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.

72 W Nd:Y3Al5O12 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%.

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

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.

https://iopscience.iop.org/article/10.1143/JJAP.41.L96/pdf

T. Murai

Papers

Tetragonal vanadates YVO4 and GdVO4 – new efficient χ(3)-materials for Raman lasers

Nd3+:Y2O3 Ceramic Laser

72 W Nd:Y3Al5O12 ceramic laser

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

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