Abstract: A laser apparatus with non-collinearly phase-matched frequency mixing includes a nonlinear crystal generating an output laser beam from non-collinearly phase-matched frequency mixing of first and second input laser beams. The output laser beam is subject to walk-off in a walk-off plane. The second input laser beam is less powerful than the first input laser beam. The first input laser beam is directed to more closely align its Poynting vector to the output beam Poynting vector than in collinear phase matching. To achieve good spatial overlap in this phase matching scheme, the second input laser beam is elongated in the walk-off plane, such that the second input laser beam has a greater transverse size than the first input laser beam in the walk-off plane. This non-collinear phase matching scheme is capable of achieving an improved beam quality of the output beam, as compared to collinear phase matching with circular input beams.

Abstract: A CO2 laser that generates laser-radiation in just one emission band of a CO2 gas-mixture has resonator mirrors that form an unstable resonator and at least one spectrally-selective element located on the optical axis of the resonator. The spectrally-selective element may be in the form of one or more protruding or recessed surfaces. Spectral-selectivity is enhanced by forming a stable resonator along the optical axis that includes the spectrally-selective element. The CO2 laser is tunable between emission bands by translating the spectrally-selective element along the optical axis.

Abstract: The invention relates to a resonator mirror (4) for an optical resonator (1) of a laser device (2), especially of a gas laser or a slab waveguide laser, comprising a reflective surface (6) with a structured area (5) which spans across a region of the reflective surface (6) centered about the optical axis (5). According to one variant of the principle underlying the invention, the structured area (5) has at least one reflective surface cross-section (8, 18, 28, 38, 48, 58, 68) which is offset with respect to the reflective surface (6) outside the structured area (5) and parallel to the optical axis (A) by half of a predefined wavelength or by a whole multiple of half the predefined wavelength. According to another variant, the structured area (5) has at least two surface cross-sections (8, 18, 28, 38, 48, 58, 68) which are offset against each other and parallel to the optical axis (A) by half of a predefined wavelength or by a whole multiple of half the predefined wavelength.

Abstract: The invention relates to a method for laser welding workpieces (W), a laser beam (L) directed onto a workpiece surface having such a radiation intensity that the workpiece material of the at least one workpiece (W) to be welded is melted in the region of the laser focus (F), a vapor capillary (D) which is at least partly surrounded by a molten bath (S) forming in the region of the laser focus (F). The laser beam (L) is moved relative to the workpiece surface in a direction of advance (V) in order to produce a weld seam. According to the invention, the molten bath (S) is subjected to mechanical stress by directing a gas stream (G) onto the workpiece surface for the purpose of stabilization during welding. The invention further relates to a device (1) designed for carrying out said method.

Abstract: A CO2 laser that generates laser-radiation in just one emission band of a CO2 gas-mixture has resonator mirrors that form an unstable resonator and at least one spectrally-selective element located on the optical axis of the resonator. The spectrally-selective element may be in the form of one or more protruding or recessed surfaces. Spectral-selectivity is enhanced by forming a stable resonator along the optical axis that includes the spectrally-selective element. The CO2 laser is tunable between emission bands by translating the spectrally-selective element along the optical axis.

Abstract: A CO2 laser that generates laser-radiation in just one emission band of a CO2 gas-mixture has resonator mirrors that form an unstable resonator and at least one spectrally-selective element located on the optical axis of the resonator. The spectrally-selective element may be in the form of one or more protruding or recessed surfaces. Spectral-selectivity is enhanced by forming a stable resonator along the optical axis that includes the spectrally-selective element. The CO2 laser is tunable between emission bands by translating the spectrally-selective element along the optical axis.

Abstract: A CO2 laser that generates laser-radiation in just one emission band of a CO2 gas-mixture has resonator mirrors that form an unstable resonator and at least one spectrally-selective element located on the optical axis of the resonator. The spectrally-selective element may be in the form of one or more protruding or recessed surfaces. Spectral-selectivity is enhanced by forming a stable resonator along the optical axis that includes the spectrally-selective element. The CO2 laser is tunable between emission bands by translating the spectrally-selective element along the optical axis.

Abstract: The application relates to a method for determining the cut quality of a laser cutting process, said quality being assessed on the basis of the formation of solidification ridges along the cut face and/or burr formation on the lower edge of the cut face. In said method, a virtual laser cutting machine in a simulation program can be virtually operated with a set of values P0 from a parameter space P.

Abstract: The application relates to a method for determining the cut quality of a laser cutting process, said quality being assessed on the basis of the formation of solidification ridges along the cut face and/or burr formation on the lower edge of the cut face. In said method, a virtual laser cutting machine in a simulation program can be virtually operated with a set of values P0 from a parameter space P.