Profile
Our working group provides and enhances optical systems for highly accurate flatness measurements of plane surfaces in order to carry out tasks such as highly accurate calibrations for customers. These systems are based on deflectometric and interferometric methods. To cover the needs for measurements of larger plane surfaces (with diameters up to 1.5 m), a new measurement system is currently being set up. It will be possible to use this measurement system for measuring not only plane surfaces, but also slightly curved freeform surfaces.
Within the scope of a research cooperation project with the European X-Ray Free-Electron Laser Facility (XFEL, Hamburg), measurement procedures for measuring the form of slightly curved mirrors with nanometer accuracy are being developed and implemented, and comparison measurements are being carried out. In research projects (e.g. with partners from universities), novel interferometric approaches (shearing procedure and multiple aperture interferometry) are being investigated as to their suitability for high-accuracy form measurement.
Two PTB measurement systems are currently taking part in an international interlaboratory comparison for the high-accuracy optical flatness measurement of plane surfaces with a diameter of 300 mm.
In addition, procedures for the absolute measurement of optical wavefronts are being developed and used to characterize wavefront sensors (e.g. Shack-Hartmann wavefront sensors).
Research/Development
Topics
- Deflectometric flatness metrology
- Interferometric flatness metrology
- 1D form measurement of curved optical surfaces using the traceable multisensor system (1D-TMS)
- Form measurement of slightly curved freeform surfaces with diameters up to 1.5 meters
- Wavefront metrology for the characterization of wavefront sensors
- Developing mathematical models of measurement systems in close cooperation with PTB's Data Analysis and Measurement
Projects/Cooperation projects
Our working group cooperates with national and international partners from industry, universities, research institutions as well as metrology institutes.
- International interlaboratory comparison on flatness measurement with an aperture of 300 mm in diameter.
- DFG project with the University of Kassel: Form measurement of precision components with a dynamically tracked interferometric line sensor(3rd project phase), term: 3 years
Abgeschlossene Projekte
- DFG project with the University of Bremen: Optical surface metrology with spatially and temporally partially coherent light wave fields (OPAL), 2 project phases with a term of 5 years in the period from 2014 to 2020.
- Transfer project to industry (TransMeT: Transfer of metrological technologies) together with OPTOCRAFT GmbH, high-accuracy calibration of wavefront sensors with spatial and angular resolution, term: 2017 to 2020.
- DFG project with the University of Kassel: Form measurement of precision components with a dynamically tracked interferometric line sensor (1st and 2nd project phases), term: 5 years in the period from 2011 to 2016
- EMRP project: Metrology for movement and positioning in six degrees of freedom (IND58 6DoF), from 2013 to 2016. https://www.ptb.de/emrp/ind58-home.html
- EMRP project: Angle metrology (SIB58 Angles), from 2013 to 2016. http://www.anglemetrology.com/
- EMRP project: Optical and tactile metrology for absolute form characterisation, (IND10), from 2011 to 2014. https://www.ptb.de/emrp/ind10-home.html
Services
Information
Lecture at TU Braunschweig in the winter semester 2020/21:
Measurement data evaluation and measurement uncertainty
See https://iprom.tu-bs.de/lehre/vorlesungen/mda_munsicherheit/start
The currently valid script of this lecture is available in the GitHub repository. (https://github.com/dhueser/MDA-Vorlesung-iprom-tu-bs)