Universitaet Stuttgart, Institut fuer Technische Optik. Jahresbericht 1986/87

SIGLETIB Hannover: RO 43(6) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Institut fuer Technische Optik, Universitaet Stuttgart. Jahresbericht 1995

Available from TIB Hannover: RO 43(23) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Institut fuer Technische Optik, Universitaet Stuttgart. Jahresbericht 1994

Available from TIB Hannover: RO 43(21) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Weiterfuehrende Ansaetze in der Interferometrie. Ergebnisse des Teilvorhabens: Interferometrie an rauhen Oberflaechen mit Laserdioden Schlussbericht

State of research: Interferometric techniques with digital fringe evaluation are appropriate for precision measurements on optically polished surfaces. Problems occur, when optically rough surfaces need to be measured. Aim of research: to investigate a interferometry method to measure surface topography of rough materials by means of digital fringe evaluation. Method: the oblique incidence interferometry was selected in order to increase the poor specular reflection of rough objects and to reduce the fringe density. Results: a special oblique incidence interferometer was created using a modified Dove-Prism as a beam splitter to adapt digital fringe evaluation techniques. The required phase shifts are achieved by variations of the injection current of the laser diode. To use this method of phase-shifting an unbalanced interferometer is necessary. The effective wavelength is #lambda#_e_f_f=4.3#mu#m by the used of oblique incidence (#delta#=81 ). This effective wavelength enables us to measure a maximal step height of 1#mu#m. Object surfaces to a roughness of Ra=0.4#mu#m can be measured with a resolution of 0.05#mu#m. The field of view has a diameter of 30 mm. In this case a lateral resolution of 120#mu#m is achieved. In the next step we studied a three-wavelength-interferometer with oblique incidence. The effective wavelength of the new experimental setup is #lambda#_e_f_f=100#mu#m. Now we are able to measure vertical steps of 25 #mu#m. The other specifications are the same as for the one-wavelength-interferometer because the single-wavelength is fitted to the effective wavelength. Applications: the oblique incidence interferometry has a high potential for industrial applications. The main advantage of this interferometry method is its application onto technical surfaces to measure using digital fringe evaluation. (orig.)SIGLEAvailable from TIB Hannover: F96B206+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Oberflaechendynamik mittels photothermischer Waermewellenanalyse und Lasertechnik Abschlussbericht

TIB Hannover: FR 2735+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Weiterfuehrende Ansaetze in der Interferometrie. Ergebnisse des Teilvorhabens: Interferometrie an rauhen Oberflaechen mit Laserdioden Schlussbericht

State of research: Interferometric techniques with digital fringe evaluation are appropriate for precision measurements on optically polished surfaces. Problems occur, when optically rough surfaces need to be measured. Aim of research: to investigate a interferometry method to measure surface topography of rough materials by means of digital fringe evaluation. Method: the oblique incidence interferometry was selected in order to increase the poor specular reflection of rough objects and to reduce the fringe density. Results: a special oblique incidence interferometer was created using a modified Dove-Prism as a beam splitter to adapt digital fringe evaluation techniques. The required phase shifts are achieved by variations of the injection current of the laser diode. To use this method of phase-shifting an unbalanced interferometer is necessary. The effective wavelength is #lambda#_e_f_f=4.3#mu#m by the used of oblique incidence (#delta#=81 ). This effective wavelength enables us to measure a maximal step height of 1#mu#m. Object surfaces to a roughness of Ra=0.4#mu#m can be measured with a resolution of 0.05#mu#m. The field of view has a diameter of 30 mm. In this case a lateral resolution of 120#mu#m is achieved. In the next step we studied a three-wavelength-interferometer with oblique incidence. The effective wavelength of the new experimental setup is #lambda#_e_f_f=100#mu#m. Now we are able to measure vertical steps of 25 #mu#m. The other specifications are the same as for the one-wavelength-interferometer because the single-wavelength is fitted to the effective wavelength. Applications: the oblique incidence interferometry has a high potential for industrial applications. The main advantage of this interferometry method is its application onto technical surfaces to measure using digital fringe evaluation. (orig.)SIGLEAvailable from TIB Hannover: F96B206+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Holografisch-interferometrische Messtechnik. Ergebnisse des Teilvorhabens: Doppelpuls- und Konturlinien-Speckleholografie mit rechnergestuetzter Interferogrammauswertung Schlussbericht

Various set-ups for double-pulse TV-Holography were investigated. A double-pulse laser (Ruby laser) has been used. Two holograms were recorded with the two laser-pulses (pulse separation in microsecond range) on a CCD-sensor. The described methods are well suited for the study of vibrations. In particular with pulse separation in the range between 5 #mu#sec and 1000 #mu#sec it is possible to investigate transient events. The spatial carrier phase shift method can be applied without problems to the double pulse system, allowing quantitative evaluation. The method is easier for the applications as the classical double pulse-holographic interferometry and allows a fast evaluation of the interferogram without film development and hologram reconstruction. It is thus well suited to be used in an industrial environment. Various Speckel-Contour arrangements were investigated. The shape information was obtained by beam tilting or Wavelength change. It was shown that the Contour sensitivity in the presented systems can be continuously changed. Shape measurements of large objects and fast measurements are possible. (orig.)SIGLEAvailable from TIB Hannover: F96B790+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Asphaerenpruefung mit computergenerierten Hologrammen (CGH). Teilvorhaben: Untersuchung von Stoereinfluessen und alternative Messverfahren Schlussbericht

SIGLEAvailable from TIB Hannover: F04B636 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman

Weiterfuehrende Ansaetze in der Interferometrie. Ergebnisse des Teilvorhabens: Interferometrische Abstandsmessung an optisch rauhen Oberflaechen bei groesseren Abstaenden Schlussbericht

State of research: Absolute distance measuring systems for large distances are usually based on the principle of intensity modulated light. The achievable resolution depends on the modulation frequency. Because photodetector bandwidths arrive at a physical limit, it seems that these systems have reached their limit. Interferometric distance measurements can only be done in a relative manner and a corner cube has to be mounted at the moving object. During measurement the laser beam sould not be interrupted; measurements at technical surfaces, i.e. optically rough surfaces, can't be performed. Aim of research: In this project a new concept for interferometric, absolute distance measurements for larger distances is examined. Besides specular reflecting objects technical surfaces shall also be used as targets. Further it should be possible to perform distance measurements at rotating objects. These targets introduce an additional signal modulation which can't be handled by conventional distance measuring systems. Method: An acusto-optical modulator generates the second wavelength in a double-heterodyne interferometer. A high frequency shift is aspired to increase the system resolution. On the other hand the decreasing unambiguity can be overcome by a multiple tone technique. Signal pickup and evaluation is performed at the comparable low heterodyne frequency. Results: After pre-experiments using a HeNe laser with suppressed carrier technique (resolution 60 nm, unambiguity 28 #mu#m) a laser diode based double-heterodyne interferometer with an UHF-AOM was realised. This set-up achieves a resolution of 45 #mu#m at 0.3 m unambiguity. Unambiguity is increased to 50 m by means of a multiple tone method. The surface under test can be either a specular reflecting or diffuse scattering one. In addition distance measurements at rotating targets during system integration are possible. The system resolution is limited by the AOM frequency available at project start. Meanwhile AOM's with 9 times higher frequencies are available with comparable diffraction efficiencies. Applications: The double-heterodyne method has a high potential for industrial geodetic applications. The main advantage of this coherent method is its application onto technical surfaces. (orig.)SIGLEAvailable from TIB Hannover: F96B207+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Mikroskopische lasergestuetzte Messwerterfassung zur Mikro- und Makrostrukturanalyse

Confocal microscopy and structurated illumination have been applied to the characterization of surfaces with a roughness between 50 nm and 10 #mu#m. Laboratory devices for microscopic and macroscopic topometry have been built, and their practicability has been proved. Confocal microscopy using a Nipkow disk is especially suited for the analysis of fine structures at a lateral resolution of <1 #mu#m. Structurated illumination can be used for rapid macrostructure analysis, e.g. in opthalmology. Data acquisition could be reduced to 80 ms maintaining the high resolution and robustness of the method. An assessory for a 3D microscope developed for both microscopic and macroscopic topometry makes quantitative measurements at real surfaces possible. (WEN)SIGLEAvailable from TIB Hannover: F97B163+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman