Abstract: Apparatus for determining geometrical parameters of a laser beam includes an optical system, a device for output coupling radiation, a beam diagnostic device, and a reflector element. The optical system focuses the laser beam into a processing region. The device for output coupling radiation couples out radiation that runs through the optical system in a direction opposite to a direction of the laser beam. The reflector element has a first surface which is partially reflecting and curved, where the curvature is equal to a mean curvature of a wave front of the laser beam in a positioning region of the reflector element.

Abstract: An apparatus for the determination of geometric parameters of a laser beam, such as, for example, the beam diameter or the focus diameter. The apparatus includes a device for the emission of a laser beam into an active region, a detector arrangement, which can be positioned in the active region, a device for the provision of a relative movement between the laser beam and the detector arrangement, and a device for the registration and evaluation of a temporally varying signal of the detector arrangement. The detector arrangement includes at least one light guide, at least two flight-diffusing structures, and at least one light-sensitive sensor. The light guide has a light-emitting surface and a light-conducting region, with an elongated shape. The at least two light-diffusing structures are essentially extended along two different directions.

Abstract: An apparatus for the determination of geometric parameters of a laser beam, such as, for example, the beam diameter or the focus diameter. The apparatus includes a device for the emission of a laser beam into an active region, a detector arrangement, which can be positioned in the active region, a device for the provision of a relative movement between the laser beam and the detector arrangement, and a device for the registration and evaluation of a temporally varying signal of the detector arrangement. The detector arrangement includes at least one light guide, at least two flight-diffusing structures, and at least one light-sensitive sensor. The light guide has a light-emitting surface and a light-conducting region, with an elongated shape. The at least two light-diffusing structures are essentially extended along two different directions.