Our working group develops and applies measurement technologies for optical systems for measurements with the smallest possible measurement uncertainty. We determine form measurement with quantities such as sphericity, wave aberration and the radius of sphere segments. We also determine other quantities – such as the homogeneity and refractive index of different types of glass or liquids, the wedge angle, the transmission of optical components that modify the form of beams, and the optical rotation of quartz control plates. To generate a traceability chain, it is also necessary to investigate the measurement accuracy of the modulation transfer function of lenses.
Working Group 4.22, Flatness Metrology, deals with the measurement of flat surfaces, whereas Working Group 4.24, Asphere Metrology, is responsible for the measurement of aspheres.

• Form measurement for spheres: Interferometry and radius measurement

• Traceable Multi Sensor method (TMS) for form metrology of curved optical surfaces

• Applications for mathematics-based measuring methods in close cooperation with PTB’s Working Group 8.42 which deals with Data Analysis and Measurement Uncertainty

• Developing a form measuring device for free-form surfaces with a diameter of up to 1.5 m, together with the Flatness Metrology and Asphere Metrology Working Groups.

• Investigating the measurement accuracy of the modulation transfer function of lenses

In research projects, the working group cooperates with international partners from industry and universities along with research and metrology institutes.

The working group offers the following calibrations:

• Sphericity and radius measurement of sperical sections
• Refractive index measurement
• Transmission measurement on beam-shape-changing components
• Polarimetric calibration of quartz control plates

• Selected publications