Search

Your search keyword '"Wartmann, Rolf"' showing total 471 results
Start Over Author "Wartmann, Rolf"

Refine your results

more »

more »

more »

more »
471 results on '"Wartmann, Rolf"'

451. Die Prognosefähigkeit von Kennzahlen

Author

Perlitz, Manfred, Besters, Hans, editor, von Colbe, Walther Busse, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Lutter, Marcus, editor, Schubert, Werner, editor, Wartmann, Rolf, editor, and Perlitz, Manfred

Published
1973
Full Text
View/download PDF

457. Problemstellung und Aufbau der Arbeit

Author

Niebling, Helmut, Besters, Hans, editor, von Colbe, Walther Busse, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Lutter, Marcus, editor, Schubert, Werner, editor, Wartmann, Rolf, editor, and Niebling, Helmut

Published
1973
Full Text
View/download PDF

458. Modeling, simulation, and analysis of birefringent effects in plastic optics

Author

Anand Asundi, Achyut Adhikari, Mazuray, Laurent, Wartmann, Rolf, Wood, Andrew P., School of Mechanical and Aerospace Engineering, Proceedings of SPIE - Optical Systems Design 2015: Optical Design and Engineering VI, and Centre for Optical and Laser Engineering

Subjects
Photoelasticity, Birefringence, Materials science, business.industry, Polarimetry, Plastic, Polarization (waves), Finite element method, Engineering::Mechanical engineering [DRNTU], Stress (mechanics), Optics, Residual stress, Solid mechanics, Composite material, business
Abstract

Plastic optics has been widely used in different application. They have been facing birefringent effects during manufacturing or during certain application. Finite element modeling of plastic optics in CAD interface is done along with experimental and theoretical comparison of the specimen with the help of solid mechanics and image processing. Low birefringence plastic optics is chosen for the experiment and varying load is applied to observe the characteristics both in experiment and simulation. Low birefringence polariscope was used to measure the birefringence in the plastic specimen. Birefringence is caused due to many effects like stress induced birefringence temperature induced due to thermal gradient and pressure during manufacturing. Here stress is induced on low birefringence specimen by two point compression loading and is compared on the base of solid mechanics, finite element modeling and image processing. The results were found to be similar and convincing. Published version

Published
2015

459. Zusammenfassung der Ergebnisse

Author

Steffen, Reiner, Besters, Hans, editor, von Colbe, Walther Busse, editor, Engelhardt, Werner, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Lutter, Marcus, editor, Wartmann, Rolf, editor, and Steffen, Reiner

Published
1977
Full Text
View/download PDF

461. Zusammenfassung

Author

Perlitz, Manfred, Besters, Hans, editor, von Colbe, Walther Busse, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Lutter, Marcus, editor, Schubert, Werner, editor, Wartmann, Rolf, editor, and Perlitz, Manfred

Published
1973
Full Text
View/download PDF

462. Realization of low-loss mirrors with sub-nanometer flatness for future gravitational wave detectors

Author

L. Pinard, D. Forest, Romain Bonnand, Benoit Sassolas, N. Morgado, R. Flaminio, Jerome Degallaix, C. Michel, G. Billingsley, Benítez, Pablo, David, Stuart, de la Fuente, Marta C., Erdmann, Andreas, Kidger, Tina E., Mazuray, Laurent, Raynor, Jeffrey M., Smith, Daniel G., Tissot, Jean-Luc M., Wartmann, Rolf, Wood, Andrew P., and Wyrowski, Frank

Subjects
Physics, Gravitational-wave observatory, Gravitational wave, business.industry, Flatness (systems theory), Detector, Michelson interferometer, LIGO, law.invention, Finesse, Optical coating, Optics, law, business
Abstract

The second generation of gravitational wave detectors will aim at improving by an order of magnitude their sensitivity versus the present ones (LIGO and VIRGO). These detectors are based on long-baseline Michelson interferometer with high finesse Fabry-Perot cavity in the arms and have strong requirements on the mirrors quality. These large low-loss mirrors (340 mm in diameter, 200 mm thick) must have a near perfect flatness. The coating process shall not add surface figure Zernike terms higher than second order with amplitude >0.5 nm over the central 160 mm diameter. The limits for absorption and scattering losses are respectively 0.5 and 5 ppm. For each cavity the maximum loss budget due to the surface figure error should be smaller than 50 ppm. Moreover the transmission matching between the two inputs mirrors must be better than 99%. We describe the different configurations that were explored in order to respect all these requirements. Coatings are done using IBS. The two first configurations based on a single rotation motion combined or not with uniformity masks allow to obtain coating thickness uniformity around 0.2 % rms on 160 mm diameter. But this is not sufficient to meet all the specifications. A planetary motion completed by masking technique has been studied. With simulated values the loss cavity is below 20 ppm, better than the requirements. First experimental results obtained with the planetary system will be presented.

Published
2012

463. Micro-holographic methods for sub-micrometer grating fabrication in fused silica with UV femtosecond laser

Author

Vladimir Mezentsev, Ruslan K. Nasyrov, David N. Nikogosyan, Mykhaylo Dubov, Ian Bennion, Alexander G. Poleshchuk, Mazuray, Laurent, Wartmann, Rolf, Wood, Andrew, Tissot, Jean-Luc, and Raynor, Jeffrey M.

Subjects
Distributed feedback laser, Materials science, Holographic grating, business.industry, Physics::Optics, Grating, Laser, law.invention, Ultrasonic grating, Optics, Fiber Bragg grating, law, Blazed grating, Femtosecond, Optoelectronics, Physics::Atomic Physics, business
Abstract

The optical layouts incorporating binary phase diffractive grating and a standard micro-objective were used for femtosecond microfabrication of periodical structures in fused silica. Two beams, generated in Talbot type interferometer, interfered on a surface and in the bulk of the sample. The method suggested allows better control over the transverse size of the grating pitch, and thus control the reflection strength of the waveguide or fibre grating. We present the examples of direct inscription of the sub-micrometer periodical structures using a 267 nm femtosecond laser radiation.

Published
2008

464. Gang der Untersuchung

Author

Kroesen, Alfred, Besters, Hans, editor, von Colbe, Walther Busse, editor, Engelhardt, Werner, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Wartmann, Rolf, editor, and Kroesen, Alfred

Published
1983
Full Text
View/download PDF

465. Zusammenfassung

Author

Chamoni, Peter, Besters, Hans, editor, von Colbe, Walther Busse, editor, Engelhardt, Werner, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Maßberg, Wolfgang, editor, Schwark, Eberhard, editor, Wartmann, Rolf, editor, and Chamoni, Peter

Published
1986
Full Text
View/download PDF

466. Zusammenfassung

Author

Wäscher, Gerhard, Besters, Hans, editor, von Colbe, Walther Busse, editor, Engelhardt, Werner, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Wartmann, Rolf, editor, and Wäscher, Gerhard

Published
1982
Full Text
View/download PDF

467. Ausblick

Author

Weber, Martin, Besters, Hans, editor, von Colbe, Walther Busse, editor, Engelhardt, Werner, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Wartmann, Rolf, editor, and Weber, Martin

Published
1983
Full Text
View/download PDF

468. Einführung

Author

Domsch, Michel, Besters, Hans, editor, Busse von Colbe, Walther, editor, Engelhardt, Werner, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Lutter, Marcus, editor, Wartmann, Rolf, editor, and Domsch, Michel

Published
1980
Full Text
View/download PDF

469. Schlußwort

Author

Lutter, Marcus, Besters, Hans, editor, von Colbe, Walther Busse, editor, Engelhardt, Werner, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Lutter, Marcus, editor, and Wartmann, Rolf, editor

Published
1977
Full Text
View/download PDF

470. Zur Einführung

Author

von Colbe, Walther Busse, Besters, Hans, editor, von Colbe, Walther Busse, editor, Engelhardt, Werner, editor, Jaeger, Arno, editor, Laßmann, Gert, editor, Lutter, Marcus, editor, and Wartmann, Rolf, editor

Published
1977
Full Text
View/download PDF

471. Using machine-learning to optimize phase contrast in a low-cost cellphone microscope.

Author

Diederich B, Wartmann R, Schadwinkel H, and Heintzmann R

Subjects
Algorithms, Light, Lighting economics, Lighting instrumentation, Microscopy, Phase-Contrast economics, Printing, Three-Dimensional, Smartphone economics, Machine Learning, Microscopy, Phase-Contrast instrumentation, Smartphone instrumentation
Abstract

Cellphones equipped with high-quality cameras and powerful CPUs as well as GPUs are widespread. This opens new prospects to use such existing computational and imaging resources to perform medical diagnosis in developing countries at a very low cost. Many relevant samples, like biological cells or waterborn parasites, are almost fully transparent. As they do not exhibit absorption, but alter the light's phase only, they are almost invisible in brightfield microscopy. Expensive equipment and procedures for microscopic contrasting or sample staining often are not available. Dedicated illumination approaches, tailored to the sample under investigation help to boost the contrast. This is achieved by a programmable illumination source, which also allows to measure the phase gradient using the differential phase contrast (DPC) [1, 2] or even the quantitative phase using the derived qDPC approach [3]. By applying machine-learning techniques, such as a convolutional neural network (CNN), it is possible to learn a relationship between samples to be examined and its optimal light source shapes, in order to increase e.g. phase contrast, from a given dataset to enable real-time applications. For the experimental setup, we developed a 3D-printed smartphone microscope for less than 100 $ using off-the-shelf components only such as a low-cost video projector. The fully automated system assures true Koehler illumination with an LCD as the condenser aperture and a reversed smartphone lens as the microscope objective. We show that the effect of a varied light source shape, using the pre-trained CNN, does not only improve the phase contrast, but also the impression of an improvement in optical resolution without adding any special optics, as demonstrated by measurements.

Published
2018
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results