Abstract: The invention relates to an arrangement for producing a Bessel beam (5), comprising a beam-forming element (2), which transforms a beam (1) incident as a plane electromagnetic wave into a Bessel beam (5). According to the invention, the beam-forming element (2) comprises at least one annular lens (3, 3?) and a Fourier optical unit, e.g. in the form of a Fourier lens (4).

Abstract: The invention relates to an arrangement for producing a Bessel beam (5), comprising a beam-forming element (2), which transforms a beam (1) incident as a plane electromagnetic wave into a Bessel beam (5). According to the invention, the beam-forming element (2) comprises at least one annular lens (3, 3?) and a Fourier optical unit, e.g. in the form of a Fourier lens (4).

Abstract: A device for contactless optical distance measurement includes a polychromatic light source, a light analysis unit and a measurement head. The measurement head has an aperture opening and an optical lens system, which has a chromatic longitudinal aberration. The optical lens system includes a first refractive lens element and a second refractive lens element. At least one of the refractive lens elements has at least one aspherical lens surface, and the first refractive lens element and/or the second refractive lens element has an optical material with an Abbe number 20<=Vd<=41. The optical lens system has such a chromatic longitudinal aberration that a measurement region, which equals an axial focal shift of the optical lens system between the wavelengths of 450 nm and 700 nm, is between 0.2 mm inclusive and 10 mm inclusive.

Abstract: A device for contactless optical distance measurement includes a polychromatic light source, a light analysis unit and a measurement head. The measurement head has an aperture opening and an optical lens system, which has a chromatic longitudinal aberration. The optical lens system includes a first refractive lens element and a second refractive lens element. At least one of the refractive lens elements has at least one aspherical lens surface, and the first refractive lens element and/or the second refractive lens element has an optical material with an Abbe number 20?V d?41. The optical lens system has such a chromatic longitudinal aberration that a measurement region, which equals an axial focal shift of the optical lens system between the wavelengths of 450 nm and 700 nm, is between 0.2 mm inclusive and 10 mm inclusive.

Abstract: The invention is directed to a method for determining the image quality of an optical imaging system and to the use of the method according to the invention for determining the influence of samples on the amplitude distribution and phase front distribution of the illumination light, of which the amplitude distribution is known in particular.

Abstract: Point scanning Laser Scanning Microscope with an element arranged in or near a pupil plane of the beam path between the probe and detection for separation of illumination and detection beams, which element comprises a reflecting or transmitting first region for the transmission of the illumination beam and a transmitting or reflecting second region, lying essentially outside the first region, for the transmission of the probe light, whereby advantageously manipulating devices for the variation of the size and/or the form of the first and/or second region are provided and a method for the adjustment of the microscope with the element wherein the manipulation of the manipulating devices takes place by means of a control circuit.

Abstract: The invention is directed to a method for determining the image quality of an optical imaging system and to the use of the method according to the invention for determining the influence of samples on the amplitude distribution and phase front distribution of the illumination light, of which the amplitude distribution is known in particular.

Abstract: An axially optically pumped laser 11 is penetrated coaxially by a target beam .lambda..sub.2. This penetration of the pumped laser occurs via light conductor 2 by means of laser diode 31. The pumped laser 11 can be an erbium--YAG laser. For this purpose, the dispersion, diffraction and reflection of an incoupling optic 12, of laser 11 and a focusing device 13 are suitably matched to each other in order that the pump light .lambda..sub.3, work beam .lambda..sub.1 and target beam .lambda..sub.2 are suitably guided and are suitable for small diameters. The laser arrangement is suitable as a medical device for ears, nose and throat and eyes and can be utilized with an endoscope.

Abstract: An apparatus for laser machining by creating a plurality of discrete and separate beams which are sent to a deflecting device including a support and a plurality of individual elements that act independently and are individually controlled to machine different points on the workpiece simultaneously.

Abstract: For defined ablation of a surface, successive partial regions of equal surface area are acted on by a radiation source, preferably a laser, through an optical system. The partial regions are smaller as regards surface area than the whole surface to be processed, so that the respective radiation source can be dimensioned in a less costly manner. Telescope optics with conical surfaces serve as optical systems suitable for this purpose.

Abstract: An improved slab-waveguide CO.sub.2 laser which includes two parallel, rectangular, flat, spaced-apart, slab electrodes whose surfaces excite a laser gas and guide laser light in a plane perpendicular to the surfaces of the slab electrodes. The component of the light propagating parallel to the electrode surfaces is not guided and is acted on only by resonator mirrors which form an unstable resonator. The improved slab-waveguide CO.sub.2 laser operates on a single vibrational transition of the CO.sub.2 molecule by employing wavelength selective optics.

Abstract: The reflecting surfaces within the resonator are minimized in an unstable laser resonator having a radially-dependent output end reflection profile and a passive Q-switch so that the least possible competing resonator geometries can be formed. For this purpose, a saturable absorber foil can be provided as a passive Q-switch element mounted so as to be inclined with respect to the optical axis. Furthermore, it is advantageous to use an output reflector having highly precise parallel boundary surfaces and to align this output reflector with high precision parallel to the end surfaces which delimit the laser medium.

Abstract: A detector is disclosed which includes an elliptical hollow mirror and a tube having a reflecting inner surface for conducting the light emitted by a specimen under investigation in a scanning electron microscope. A vacuum window is seated at the outer end portion of the tube directly ahead of a receiver.