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Common Lasers and Parameters
Published in Mark Steven Csele, Laser Modeling, 2017
An alternative device is the optically pumped semiconductor laser (OPSL), which has a structure much like a VCSEL and is pumped by another diode laser. Often configured much like a thin-disk laser (see Section 8.4.4) in which the semiconductor laser with HR is attached to a heatsink, semiconductor media used in this way exhibit a large pump absorption band, allowing pumping by a wide range of wavelengths. Costs of the system are thus reduced since the pump diode does not need accurate temperature control. Such a laser has all the features of a thin-disk laser, including scalability of output power.
Laser tube cutting—Comparison of new types of K-joints and their SCF with standard solutions
Published in Amin Heidarpour, Xiao-Ling Zhao, Tubular Structures XVI, 2018
S. Herion, O. Fleischer, J. Hrabowski, S. Raso, A. Valli, A. Mastropasqua, E. Bononi
In the last years high power solid state laser have been developed: disk laser, where radiation is generated in a disk shaped gain medium (crystal doped with neodymium and/or ytterbium), or fiber laser, where radiation is generated in a doped optical fiber. In both cases the wave length is 1,06–1,08 μm. The and laser beam is guided to the collimating and focusing optics by a thin fiber.
Full penetration welding of thick high tensile strength steel plate with high-power disk laser in low vacuum
Published in Welding International, 2018
Seiji Katayama, Ryouji Ido, Koji Nishimoto, Masami Mizutani, Yousuke Mizutani
The continuous output power disk laser used in the study was a disk laser with a maximum laser power of 16 kW. The beam parameter product, which expresses the beam output, was 8 mm*mrad. Figure 1 is a schematic diagram of the structure of the experimental apparatus and the welding conditions. The laser beam is carried by a fibre with a core diameter of ø0.2 mm and optically guided to a long-focus laser head (focal length: approximately 1 m) focussed on the surface of the specimen in an acrylate vacuum chamber. The beam spot diameter was ø0.5 mm, the peak power density was approximately 160 kW/mm [2] at a laser power of 16 kW with Gaussian distribution assumed. The laser was irradiated perpendicularly onto the specimen and melt-run welding performed with a laser power of 16 kW, welding speed of 5 ~ 25 mm/s and atmospheric pressures of 0.1, 10 and 101 kPa. Two rotary pumps with an exhaust speed of 150 L/min and one rotary pump with an exhaust speed of 500 L/min were used to reduce the pressure in the vacuum chamber to the pressure specified for the experiment and after the pressure was reduced to about 0.03 kPa, N2 was introduced to maintain the specified low-pressure atmosphere. The incident laser light passes through protective glass, set in a chimney more than 500 mm high attached in the roof of the vacuum chamber in order to prevent adhesion of metal vapour. Furthermore below the glass was set the inlet port for the shielding gas and the flow of this gas was directed to prevent such adhesion to the protective glass. In experiments under the large atmospheric pressure of 101 kPa, the specimen was removed from the vacuum chamber and melt-run welding carried out with nitrogen shielding gas fed through a 16 mm side nozzle following the welding direction at a rate of 50 L/min and an angle of 45 degrees. In order to examine the bead width and penetration depth under all of these welding conditions, three cross-sectional areas per bead were measured and the mean value found.