Universitãt Stuttgart

Carl Mahr Holding Gmbh

Baden-Wurttemberg Stiftung Ggmbh

Christof Pruss

Wolfgang Osten

Alois Herkommer

Klaus Körner

Klaus Koerner

Daniel Claus

Goran Baer

Harald Giessen

Aiko Ruprecht

David Hopp

Simon Thiele

Giancarlo Pedrini

Reinhard Berger

Christian Kohler

Christian Schober

Ulrich Droste

Tobias Wiesendanger

A method of fabricating an imaging system as well as to a corresponding imaging system. The method includes providing a substrate; and forming, by means of aD-printing technique, aD structure on the substrate, wherein the forming of theD structure includes forming a stack of at least two diffractive optical elements in a single printing step.

Method of fabricating an imaging system and corresponding imaging system

The present invention relates to a method and an assembly for chromatic confocal spectral interferometery, in particular also for spectral domain OCT (SD-OCT) using multi-spectral light. A multiple (e.g. two, three, four, etc.) axial splitting of foci in the interferometric object arm is performed using a multifocal (e.g. bifocal, trifocal, quattro-focal, etc.) optical component, forming thereby at least two, three or even several groups of chromatically split foci in the depth direction. The multifocal optical component is made of a diffractive optical element () and a Schwarzschild objective (). At least two, three, four or even more differently colored foci of different groups of foci coincide in at least one confocal point in the object space of the setup. Thus, at least two, three or even more spectral wavelets are formed in the case of optical scanning of an object measurement point and spectral detection in the wavenumber domain, which wavelets are at least slightly spectrally separated from each other. This results in a significant increase in the optical primary data in the wavenumber domain and reduces the trade-off of the chromatic confocal spectral interferometry between axial measurement range and depth resolution. From the detected data, it is possible to calculate tan (alpha) as the quotient of the absolute phase shift delta_phi and the associated wavenumber difference delta_k, the Fourier transform over the spectral data, in order to respectively determine the optical path difference.

Method and assembly for chromatic confocal spectral interferometry or spectral domain oct

An interferometer for areally measuring an optically smooth surface is presented, including means for illuminating a surface region with a plurality of discrete object waves from different directions and comprising means which, on a detector, superimpose object waves reflected at the surface onto a reference wave that is coherent with a plurality of object waves in order to form an interferogram. The interferometer is distinguished by virtue of it being configured to illuminate the surface with a plurality of object waves at the same time and produce the reference wave by way of a Fizeau beam splitter plate or a Fizeau objective, and by virtue of the interferometer including an interferometer stop that is arranged in the beam path upstream of the detector, and imaging optics, wherein the interferometer stop is situated within, or slightly outside of, the Fourier plane of the imaging optics and said interferometer stop filters the object waves reflected by the surface.

Interferometer using tilted object waves and comprising a Fizeau interferometer objective

The invention relates to a method for calibrating a measuring device, comprising the following steps: moving, with finite accuracy and thus with positioning error, to various points that lie in a testing volume of the measuring device and that can be characterized by spatial and/or angular coordinates, generating measurement signals at the respective points, and determining parameters of a computing model of the measuring device from the measurement signals and the spatial and/or angular coordinates. The method is characterized in that a coordinate system to which the coordinates of the points of the testing volume relate is defined from points moved to with error, by associating predetermined coordinate values with exactly six coordinates of three points.

Method for calibrating a measuring device

Disclosed herein is a measuring probe and an arrangement for measuring spectral absorption, preferably in the infrared. Furthermore, the invention relates to a method for spectroscopically measuring absorption. The measuring probe may comprise a cutting apparatus configured to cut a slice or respectively flap off of a sample to be measured; a measuring gap configured to accommodate the sample slice; an optical window element for coupling measuring light into, or respectively out of the measuring gap; and an end reflector designed and arranged to reflect the measuring light propagated through the measuring gap back into the measuring gap. The arrangement for measuring spectral absorption may comprise the measuring probe, a light source and an apparatus for the spectral analysis of the measuring light coupled out of the measuring gap.

Method and apparatus for optical absorption measurements

The invention relates to a method and arrangement for short coherence holography for distance measurement, for profile detection and/or for 3D detection of one or more object elements and/or object areas and/or objects or for readout of holographic volume memories with a holographic interferometer and with at least one short coherence light source. For each optically detected object element in the hologram the holographic interferometer has an optical path difference clearly unequal to zero. At least one spectrally integrally detecting, rastered detector is arranged. The short coherence light source with frequency comb is designed with the optical delay length Y. Detected holograms are digitally reconstructed. Relative distances of object elements are digitally calculated from the hologram reconstructions, so that a 3D point cloud of object elements and/or object areas and/or objects is produced. Data can be read out optically in parallelized form from holographic volume memories or three-dimensionally structured signatures.

Method and arrangement for short coherence holography

The invention relates to an improved encoding disk for an optical rotation angle sensor or a rotary encoder, an optical rotation sensor or rotary encoder comprising an improved encoding disk, and a method for optically correcting or compensating for an angle measuring error of a rotary encoder, in particular an angle measuring error which is contingent on a displacement or decentralization of the encoding disk. The encoding disk () comprises at least one measuring track () and at least one compensating track (), wherein the measuring track () is in a first radial region of the encoding disk (); and the compensating track () is centered with regard to the measuring track () on a second radial region of the encoding disk () so that the center of the measuring track () coincides with the center of the compensating track (). The compensating track () is preferably designed such that at least one part of the light incident on a region of the compensating track is deflected by the compensating track () radially in the direction of the axis through the common center of the compensating track () and the measuring track (). The direction of the readout light which is deflected by the compensating track preferably intersects the axis through the common center of the compensating track and the measuring track, wherein the distance between the compensating track and said intersection corresponds to the length of the light path between the compensating track and the measuring track. The readout light can be coherent or incoherent. The radius of the compensating track can be less than, greater than, or equal to the radius of the measuring track. The compensating track () preferably has a diffractive structure.

Device and method for optically compensating for the measuring track decentralization in rotation angle sensors

An interferometric confocal method and assembly for terabyte volume optical data memories couples two-beam spectral interferometry to chromatic confocal technology and permits a longitudinal splitting of foci in the memory volume, with the foci having limited diffraction. A spectrometer is located downstream of the interferometer with confocal discrimination in the beam path. A diffractive optical zone lens (DOZE) with a usage of the first diffraction order is introduced into the interferometric beam path to achieve longitudinal chromatic splitting. The interferometer can be a fiber-coupled interferometer with a retroreflector in the fiber-coupled reference arm and with wavelength-dependent optical path difference modification by dispersion or diffraction. The optical path difference in the interferometer is set so that easily detectable wavelets are formed from detectable interferograms by spectral analysis.

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Ostfildern, Germany

Christof Pruss