Abstract: A device for modifying a region of a substrate includes a laser radiation source for pulsed laser radiation. A transmissive medium having a higher intensity-dependent refraction index than air is arranged between a laser machining head and the substrate such that an individual pulse of the pulsed laser radiation from the laser machining head is deflected through the transmissive medium and across a thickness of the substrate from an original focal depth to a focal depth different from the original focal depth to modify the substrate along a beam axis of the laser radiation in a region of a recess or through-opening to be formed in the substrate without removing an amount of the substrate material necessary to form the recess or through-opening. A length between the focal depths is greater than and extends across the thickness of the substrate.

Abstract: A method for introducing at least one cutout, in particular in the form of an aperture, into a sheetlike workpiece having a thickness of less than 3 mm, involving detecting a laser beam onto the surface of the workpiece, selecting the exposure time of the laser beam to be extremely short so that only a modification of the workpiece concentrically around a beam axis of the laser beam occurs, such a modified region having defects resulting in a chain of blisters, and, as a result of the action of a corrosive medium, anisotropically removing material by successive etching in those regions of the workpiece that are formed by the defects and have previously been modified by the laser beam, resulting, along the cylindrical zone of action, in producing a cutout as an aperture in the workpiece.