Abstract: A Q-switched CO2 laser material processing system with acousto-optic modulators (AOM) is employed, on the one hand, inside the resonator for Q-switching the CO2 laser and, on the other hand, externally for efficient suppression of the radiation feedback between a laser and workpiece. The frequency shift of the radiation diffracted at the AOM is taken into account which exactly corresponds to the excitation frequency of the acoustic wave in the AOM crystal under the aspect of the amplification of the radiation in the active medium. Since this frequency shift significantly reduces the amplification of the radiation, it has to be avoided in the Q-switching process, which is achieved, by means of a tandem of two AOMs with identical excitation frequencies but with the acoustic waves propagating in opposite directions in the crystal. The frequency shift advantageously suppresses radiation feedback between the laser and workpiece.

Abstract: A Q-switched CO2 laser material processing system with acousto-optic modulators (AOM) is employed, on the one hand, inside the resonator for Q-switching the CO2 laser and, on the other hand, externally for efficient suppression of the radiation feedback between a laser and workpiece. The frequency shift of the radiation diffracted at the AOM is taken into account which exactly corresponds to the excitation frequency of the acoustic wave in the AOM crystal under the aspect of the amplification of the radiation in the active medium. Since this frequency shift significantly reduces the amplification of the radiation, it has to be avoided in the Q-switching process, which is achieved, by means of a tandem of two AOMs with identical excitation frequencies but with the acoustic waves propagating in opposite directions in the crystal. The frequency shift advantageously suppresses radiation feedback between the laser and workpiece.

Abstract: Subject matter of the invention is a CO2 laser that permits a rapid power modulation, particularly a highly efficient Q-switching. The key concept is the sub-division of the resonator into a high-power branch, containing inter alia the active medium (1), and a low-power feedback branch (14), in which the power-sensitive beam-shaping elements, particularly the modulators, are arranged. This is made possible by a suitable arrangement of a polarisation beam splitter (5) and a ?/4-phase shifter (2). The free adjustability of an angle ? between said two components permits the extremely flexible realisation of various operating modes, particularly the optimisation of the feedback degree during pulse generation.

Abstract: The present invention is a method and system for the drilling of holes in a workpiece within a diameter range of 20 ?m to 500 ?m by means of laser radiation. The invention utilizes the beam quality of a laser beam as well as: the polarization of the laser radiation; the parameters of the impulses of the laser used; and, the type and pressure of the process gas used. The method and system utilize means for focusing laser radiation, in particular the ratio of the beam diameter at the site of the focusing element and its focal distance, and wherein the focusing is done in coordination with the beam quality number and wave length and other factors. A first working gas supports the formation of the hole shape and accelerates the drilling process; and, a second working gas is utilized to improve the surface quality of the drilling walls.

Abstract: The present invention is a method and system for the drilling of holes in a workpiece within a diameter range of 20 ?m to 500 ?m by means of laser radiation. The invention utilizes the beam quality of a laser beam as well as: the polarization of the laser radiation; the parameters of the impulses of the laser used; and, the type and pressure of the process gas used. The method and system utilize means for focusing laser radiation, in particular the ratio of the beam diameter at the site of the focusing element and its focal distance, and wherein the focusing is done in coordination with the beam quality number and wave length and other factors. A first working gas supports the formation of the hole shape and accelerates the drilling process; and, a second working gas is utilized to improve the surface quality of the drilling walls.

Abstract: The invention relates to a tube system for supplying a fluid, preferably for subsoil irrigation. Said tube system consists of an inner tube (2) which supplies the fluid and is arranged inside an outer tube (1?) at a distance therefrom. A buffer volume is formed between the inner tube (2) and the outer tube (1), said buffer volume being sub-divided into provision chambers (8) by constrictions (7) of the outer tube (1?). The fluid (3) supplied by means of the inner tube (2) enters the chambers (8) by means of portioning holes (4). The outer tube (1?) preferably consists of a porous material. In order to fill the buffer volume (5) with a fluid, the cross-section of the openings of the outer tube (1) is essentially smaller than the cross-section of the portioning holes (4) of the inner tube (2). To this end, the inner tube (2) consists of a fluid-impermeable material, and the outer tube consists of a porous or perforated material.

Abstract: The invention is directed to a beam-shaping unit for generating a beam bundle which is focused in a punctiform manner, propagates in a ring shape, and has a radiationless central area, comprising a focusing lens, a first axicon and a second axicon, and to an arrangement with a beam-shaping unit of this kind for introducing radiation energy into a workpiece comprising weakly absorbent material which is arranged between a first resonator mirror and a second resonator mirror. The first resonator mirror which is arranged in front of the workpiece in the radiating direction is located in the radiationless central area. The radiation energy can be absorbed to the maximum extent by repeatedly passing through the same interaction volume in the workpiece.

Abstract: The invention is directed to a beam-shaping unit for generating a beam bundle which is focused in a punctiform manner, propagates in a ring shape, and has a radiationless central area, comprising a focusing lens, a first axicon and a second axicon, and to an arrangement with a beam-shaping unit of this kind for introducing radiation energy into a workpiece comprising weakly absorbent material which is arranged between a first resonator mirror and a second resonator mirror. The first resonator mirror which is arranged in front of the workpiece in the radiating direction is located in the radiationless central area. The radiation energy can be absorbed to the maximum extent by repeatedly passing through the same interaction volume in the workpiece.

Abstract: Disclosed is a method for separating optical fibers by means of CO2 laser radiation, appllicable with various types and sizes of fibers with or without cladding as well as with fiber bunches and fiber components. According to the inventive method, separation is performed by means of a special impulse regime adapted to each material, whereby minuscule volumes of material are removed along a line in a sawing-like process until complete separation has been achieved.

Abstract: A solid workpiece, e.g. a glass tube, is shaped by a focussed beam of visible light or light in an adjacent portion of the electromagnetic spectrum in a material removal, cutting or drilling operation and is heat-treated or remelted or shaped in a plastic state by heating that second beam which is less focussed or even divergent. The beams derive from a common source, a CO.sub.2 laser, and pass through a splitting deflecting system so that the beams can be directed simultaneously either parallel to one another or with an inclination to one another at the same or different regions of the workpiece which is held in a holder capable of both rotating the workpiece and translating same.

Abstract: An arrangement for the generation of CO.sub.2 laser pulses of high power. In a first step, the laser medium is brought by an electrical pumping pulse into a state of extremely high population inversion and, in a second step, this inversion is decayed suddenly by a Q-switching effect in such a manner, that radiation pulses of extreme power magnification arise. The power is supplied to the laser-gas discharge by a power-supply unit which permits the pulsed supply of pumping energy. The associated laser resonator is formed froma first resonator mirror with a fixed reflectivity R.sub.1,frequency-selective element,a special, highly angle-selective gas discharge tube,and a special component material transparent to the laser radiation that functions as a second resonator mirror with a variable reflectivity R.sub.2. The second unit is comprised of a modulator with a high cutoff frequency in the form of a Fabry-Perot interferometer arrangement with a rapidly changeable optical wavelength.

Abstract: An arrangement for the wavelength-selective internal intensity modulation and radiation pulse generation of high power CO.sub.2 lasers, in a high-power CO.sub.2 laser is forced to operate in the resonator at a freely selectable but fixed wavelength by means of a frequency-selective element and highly angle-selective gas discharge tubes. The possibility of rapidly Q-switching is provided by a special interferometer arrangement of variable reflectivity, functioning as an uncoupling element. The arrangement may furthermore be used for the rapid stabilization of the laser power.

Abstract: The invention relates to an apparatus for external modulation of high-efficiency CO.sub.2 laser beams of defined wavelength, particularly for use in CO.sub.2 laser material working apparatuses. According to the invention two plates made of transparent material are arranged parallel to each other, the inner surfaces of the plates are reflective and the outer surfaces are non-reflective.