Recently, interest in diode laser-pumped solid-state lasers has increased due to their advantages over flashlamp-pumped solid-state lasers. A historical overview is presented of semiconductor diode-pumped solid-state lasers beginning with work in the early 1960s and continuing through recent work on wavelength extension of these devices by laser operation on new transitions. Modeling of these devices by rate equations to obtain expressions for threshold, slope efficiency, and figures of merit is also given. >

Diode laser-pumped solid-state 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

We have carried out a detailed spectroscopic characterization of Nd: GdVO4, a new laser crystal with high effective absorption and emission cross sections. The accidental degeneracy of the upper4
F
3/2 laser level decreases the number of emission lines and creates -together with the anisotropic crystal field - high emission cross sections (7.6 × 10−19 cm2 at 1.06 µm and 300 K). In addition, the lines are strongly homogeneously broadened (1.6 nm for the 808.4 nm diode-laser pump transition). The temperature dependences of lifetime, linewidths, and cross sections have been determined. Slope efficiencies up to 57% with respect to the absorbed diode-laser pump power and output powers up to 0.8 W have been achieved at 1.06 µm from a 2 mm long crystal. Intracavity second-harmonic generation, using a KTP crystal, is demonstrated.

Spectroscopic characterization and laser performance of diode-laser-pumped Nd: GdVO4

In recent years, additive manufacturing, also known as three-dimensional (3D) printing, has emerged as an environmentally friendly green manufacturing technology which brings great benefits, such as energy saving, less material consumption, and efficient production. These advantages are attributed to the successive material deposition at designated target areas by delivering the energy on it. In this regard, lasers are the most effective energy source in additive manufacturing since the laser beam can transfer a large amount of energy into micro-scale focal region instantaneously to solidify or cure materials in air, therefore enabling high-precision and high-throughput manufacturing for a wide range of materials. In this paper, we introduce laser-based additive manufacturing methods and review the types of lasers widely used in 3D printing machines. Important laser parameters relevant to additive manufacturing will be analyzed and general guidelines for selecting suitable lasers for additive manufacturing will be provided. Discussion on future prospects of laser technologies for additive manufacturing will be finally covered.

Lasers in additive manufacturing: A review

YVO4 nano/microcrystals with multiform morphologies, such as nanoparticles, microdoughnut, micropancake, pillar structure, and microflower, have been synthesized via a facile hydrothermal route. A series of controlled experiments indicate that the shape and size of as-prepared architectures can be tuned effectively by controlling the reaction conditions, such as reaction time, vanadium sources, different organic additives, and the molar ratio of organic additive trisodium citrate (Cit3−):Y3+. It is found that Cit3− as a ligand and shape modifier has the dynamic effect by adjusting the growth rate of different facets under different experimental conditions, resulting in the formation of various geometries of the final products. The possible formation mechanisms for products with diverse architectures have been presented in detail. Additionally, we systematically investigate the luminescent properties of the YVO4:Ln3+ (Ln = Eu, Dy, Sm, and Er). Because of an efficient energy transfer from vanadate groups to...

Ln3+ (Ln = Eu, Dy, Sm, and Er) Ion-Doped YVO4 Nano/Microcrystals with Multiform Morphologies: Hydrothermal Synthesis, Growing Mechanism, and Luminescent Properties

We report on the first diode‐laser (nominal 200‐mW 10‐stripe laser diode) end‐pump lasing of Nd:YVO4. The lowest threshold (30 mW) and highest output power (120 mW) were observed from the Nd:YVO4 laser as compared to a similar Nd:YAG laser. Over 50% optical slope efficiency was obtained, the highest yet reported for diode pumping. This device performed at a 10% overall efficiency. Measurements over a 21‐nm range show the advantages of the Nd:YVO4 pump absorption band.

Highly efficient Nd:YVO4 diode‐laser end‐pumped laser

https://www.osapublishing.org/viewmedia.cfm?URI=CLEO-1987-FL4

Highly efficient diode-pumped Nd:crystal lasers

Recently Nd:YVO4 was demonstrated to outperform Nd:YAG in a diode laser end pump laser comparison [1]. Further developments in diode laser arrays and application of more optimum pump coupling schemes have led to cw output powers as high as 750 mW TEMoo at 1.06 µm, optical slope efficiencies up to 64%, and electrical to optical conversion efficiencies up to 15.8%, the highest for any single diode pumped device.

15.8% EFFICIENT DIODE LASER END PUMPED Nd:YVO4 LASER

We report the highest electrical to optical conversion efficiency (12.5%), and the highest cw output power (750 mW), from any solid state laser crystal end pumped by a single multiple stripe diode laser array. The optical slope efficiency, which refers to the 1.06 μm output power divided by the optical pump power incident on the end face of our laser crystal, was measured to be 64% in the best case and corresponds to nearly a 95% Nd quantum conversion rate, the highest yet reported.

M. Birnbaum

Papers

Highly efficient Nd:YVO4 diode‐laser end‐pumped laser

Highly efficient diode-pumped Nd:crystal lasers

15.8% EFFICIENT DIODE LASER END PUMPED Nd:YVO4 LASER

750 mW, 1.06 um, CW TEM00 output from a Nd:YVO4 laser end pumped by a single 20 stripe diode array