High power laser beam shaping for welding applications by means of diffractive elements

Laser welding by means of multi-kilowatt solid state lasers can be considerably improved if the focused welding spot is embedded in a pre-heating spot generated e.g. by an additional laser. To improve the compactness of the optical system, the same functionality can be effectively achieved by means of diffractive diffusers. Because such a diffractive optical solution may suffer from the presence of speckles, a comprehensive characterization of the laser source is performed. The paper includes the design, the compensation of the difference in the intensity levels, the fabrication and the optical performances of the fabricated DOEs. We furthermore present the functionality of the DOEs in the welding process.