METHOD AND APPARATUS FOR DETERMINING THE POSITION AND DIAMETER OF THE FOCAL POINT OF LASER BEAM

The present invention is a process and apparatus for determining the position and diameter of the focal point of a laser beam, specifically for use in material processing with a heavy-duty laser beam. In a process for determining the position and diameter of the focal point of a laser beam, specifically a heavy-duty laser beam, a rotationally symmetric reflector which reproduces a laser beam on a focal line is introduced in the path of rays of a focused laser beam. Reflected on the reflector, the laser beam is captured by way of at least one sensor which is fixedly coordinated with the reflector in the focal line, while the focal plane, the lateral position of the focal point and the diameter of the focal point are then determined by way of measured values captured in the sensor, with the sensor being shifted relative to the focusing optics of the laser beam or relative to the reflector. The output intensity of the laser is reduced to a point where the laser can be safely and unequivocally measured with the aid of sensors.