Abstract: An apparatus for processing material with focused electromagnetic radiation, comprises: a source emitting electromagnetic radiation, means for directing the radiation onto the material, means for focusing the radiation on or in the material, a unit for generating a pattern in the optical path of the electromagnetic radiation, an at least partially reflective surface in the optical path before the focus of the focused radiation, said pattern being imaged onto said at least partially reflective surface through at least part of said directing means and said focusing means, at least one detector onto which an image of the pattern is reflected by said surface and which generates electrical signals corresponding to said image, said image containing information on the position of the focus, a computer receiving said electrical signals and programmed to process said image so as to generate an electrical signal depending on the focal position, and a divergence adjustment element arranged in said optical path and adapt

Abstract: An apparatus for processing material with focused electromagnetic radiation, comprises: a source emitting electromagnetic radiation, means for directing the radiation onto the material, means for focusing the radiation on or in the material, a unit for generating a pattern in the optical path of the electromagnetic radiation, an at least partially reflective surface in the optical path before the focus of the focused radiation, said pattern being imaged onto said at least partially reflective surface through at least part of said directing means and said focusing means, at least one detector onto which an image of the pattern is reflected by said surface and which generates electrical signals corresponding to said image, said image containing information on the position of the focus, a computer receiving said electrical signals and programmed to process said image so as to generate an electrical signal depending on the focal position, and a divergence adjustment element arranged in said optical path and adapt

Abstract: A laser-assisted material-machining device comprises a laser (14) for providing a pulsed laser beam (16), a measuring arrangement (30, 32, 34, 36, 38) in order to obtain measured values of a fundamental-wave power of the laser beam and also of a power of at least one higher harmonic generated from the laser beam by frequency multiplication, and an evaluating unit (22) connected to the measuring arrangement, which has been set up to examine the quality of the laser beam (16) in a manner depending on the measured fundamental-wave power, on the measured power of the higher harmonic, and on a set radiant power of the laser (14). By formation of the quotient of the measured fundamental-wave power and of the measured power of the higher harmonic, the current conversion efficiency of the frequency multiplication can be ascertained. Said conversion efficiency is a measure of the quality of the wavefront and of the pulse duration of the laser beam (16).

Abstract: A laser-assisted material-machining device comprises a laser (14) for providing a pulsed laser beam (16), a measuring arrangement (30, 32, 34, 36, 38) in order to obtain measured values of a fundamental-wave power of the laser beam and also of a power of at least one higher harmonic generated from the laser beam by frequency multiplication, and an evaluating unit (22) connected to the measuring arrangement, which has been set up to examine the quality of the laser beam (16) in a manner depending on the measured fundamental-wave power, on the measured power of the higher harmonic, and on a set radiant power of the laser (14). By formation of the quotient of the measured fundamental-wave power and of the measured power of the higher harmonic, the current conversion efficiency of the frequency multiplication can be ascertained. Said conversion efficiency is a measure of the quality of the wavefront and of the pulse duration of the laser beam (16).