Abstract: A method for laser material processing includes generating a first pulsed laser beam that forms a first focus zone, and processing the material with the first pulsed laser beam in order to produce first modifications. The first modifications form a shielding surface. The method further includes generating a second pulsed laser beam that forms a second focus zone, which is formed in elongated fashion along a second focus zone axis and is formed by constructive interference of laser radiation that passes at an angle toward the second focus zone axis. The method further includes processing the material with the second pulsed laser beam to produce second modifications in a second section of the material. At least one part of the laser radiation passes at the angle toward the second focus zone axis impinges on the shielding surface.

Abstract: A device for aligning a processing optical assembly of a laser processing machine includes an entrance region for receiving a processing laser beam, a focus zone forming region for forming a measurement focus zone by the received processing laser beam along a target axis, and an imaging unit having a lens and a detector surface. The lens is configured to image measurement laser radiation that leaves the focus zone forming region after the measurement focus zone has been formed, along an imaging axis predefined by the target axis, onto the detector surface. The processing optical assembly is configured to shape a laser beam in the laser processing machine and to focus it along an incident beam axis so that a processing laser beam forms a preset Bessel beam focus zone in a workpiece to be processed.

Abstract: A method for selective laser-induced etching of a microhole into a workpiece includes creating a modification in the workpiece that extends from an entrance side to an exit side of the workpiece. The modification is created by a laser pulse that has an annular transverse intensity distribution. The modification delimites a cylindrical body from a residual material surrounding the modification. The method further includes introducing the workpiece with the modification into a wet-chemical etching bath for structurally separating the cylindrical body from the residual material.

Abstract: A processing optical unit for workpiece processing includes a birefringent polarizer configured to split at least one input laser beam into a pair of partial beams polarized perpendicularly to one another. The processing optical unit further includes a focusing optical unit arranged downstream of the birefringent polarizer in the beam path and configured to focus the pair of partial beams onto focus zones in a focal plane. The processing optical unit is configured to produce at least partly overlapping focus zones of the pair of partial beams.

Abstract: For material processing of a material, which is in particular for a laser beam to a large extent transparent, asymmetric shaped modifications are created transverse to the propagation direction of the laser beam. Thereby, the laser beam is shaped for forming an elongated focus zone in the material, wherein the focus zone is such that it includes at least one intensity maximum, which is transverse flattened in a flattening direction, or a transverse and/or axial sequence of asymmetric intensity maxima, which are flattened in a sequence direction. After positioning the focus zone in the material, a modification is created and the material and the focus zone are moved relative to each other in the or across to the flattening direction or in the or across to the sequence direction for forming a crack along an induced preferred direction.

Abstract: For material processing of a material, which is in particular for a laser beam to a large extent transparent, asymmetric shaped modifications are created transverse to the propagation direction of the laser beam. Thereby, the laser beam is shaped for forming an elongated focus zone in the material, wherein the focus zone is such that it includes at least one intensity maximum, which is transverse flattened in a flattening direction, or a transverse and/or axial sequence of asymmetric intensity maxima, which are flattened in a sequence direction. After positioning the focus zone in the material, a modification is created and the material and the focus zone are moved relative to each other in the or across to the flattening direction or in the or across to the sequence direction for forming a crack along an induced preferred direction.

Abstract: An optical system for shaping a laser beam includes a beam shaping element configured to receive the laser beam having a transverse input intensity profile and to impose a beam shaping phase distribution onto the laser beam. The optical system further includes a near field optical element, arranged downstream of the beam shaping element at a beam shaping distance and is configured to focus the laser beam into the focus zone. The imposed phase distribution results in a virtual optical image of the elongated focus zone located before the beam shaping element. The beam shaping distance corresponds to a propagation length of the laser beam within which the imposed phase distribution transforms the transverse input intensity profile into a transverse output intensity profile at the near field optical element.

Abstract: An optical system for shaping a laser beam includes a beam shaping element configured to receive the laser beam having a transverse input intensity profile and to impose a beam shaping phase distribution onto the laser beam. The optical system further includes a near field optical element, arranged downstream of the beam shaping element at a beam shaping distance and is configured to focus the laser beam into the focus zone. The imposed phase distribution results in a virtual optical image of the elongated focus zone located before the beam shaping element. The beam shaping distance corresponds to a propagation length of the laser beam within which the imposed phase distribution transforms the transverse input intensity profile into a transverse output intensity profile at the near field optical element.

Abstract: An optical system for shaping a laser beam includes a beam shaping element configured to receive the laser beam having a transverse input intensity profile and to impose a beam shaping phase distribution onto the laser beam. The optical system further includes a near field optical element, arranged downstream of the beam shaping element at a beam shaping distance and is configured to focus the laser beam into the focus zone. The imposed phase distribution results in a virtual optical image of the elongated focus zone located before the beam shaping element. The beam shaping distance corresponds to a propagation length of the laser beam within which the imposed phase distribution transforms the transverse input intensity profile into a transverse output intensity profile at the near field optical element.

Abstract: For material processing of a material, which is in particular for a laser beam to a large extent transparent, asymmetric shaped modifications are created transverse to the propagation direction of the laser beam. Thereby, the laser beam is shaped for forming an elongated focus zone in the material, wherein the focus zone is such that it includes at least one intensity maximum, which is transverse flattened in a flattening direction, or a transverse and/or axial sequence of asymmetric intensity maxima, which are flattened in a sequence direction. After positioning the focus zone in the material, a modification is created and the material and the focus zone are moved relative to each other in the or across to the flattening direction or in the or across to the sequence direction for forming a crack along an induced preferred direction.