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Author: ulf griesmann
Displaying records 11 to 20 of 49 records.
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11. A Toolbox for Designing and Analyzing Phase-Shifting Interferometry Algorithms with Characteristic Polynomials
Many of the recent advances in understanding of phase-shifting algorithms have yet to be incorporated into the software for commercial phase shifting interferometers. A toolbox, for the open-source computer algebra system Maxima, simplifies analysis ...
12. Power Spectral Density: Is it right?
Ulf Griesmann, John Lehan, Jiyoung Chu
We concentrate on the instrumental issues surrounding power spectral density (PSD) determination, using as an example, the most common optical shop QA tool, the Fizeau interferometer. We briefly discuss the properties of an ideal calibration method ...
13. Deformation-Free Form Error Measurements of Thin, Plane-Parallel Optics Floated on a Heavy
JiYoung Chu, Ulf Griesmann, Quandou Wang, Johannes A Soons, Eric C Benck
We describe a novel method for measuring the unconstrained flatness error of
thin, plane parallel precision optics by floating them on high-density aqueous
metatungstate solutions while measuring the flatness error with an interferometer. The
14. Computer-Generated Hologram Cavity Interferometry Test for Large X-Ray Mandrels: Design
Guangjun Gao, John P. Lehan, William W. Zhang, Ulf Griesmann, Johannes A Soons
A glancing incidence interferometric test for large x-ray mirror mandrels, using two computer generated holograms (CGH s), is described. The two CGH s are used to form a double pass glancing incidence system. One layout of the CGH-cavity glancing in ...
15. Radius Measurement of Spherical Surfaces With Large Radii-of-Curvature Using Dual-Focus Zone Plates
Quandou Wang, Guangjun Gao, Ulf Griesmann
The measurement of spherical surface radii exceeding a few meters presents a challenge, because the familiar radius-bench method requires large part displacements. Dual-focus zone plates can extend the radius-bench method to measurements of large rad ...
16. Measuring the Phase Transfer Function of a Phase-Shifting Interferometer
JiYoung Chu, Quandou Wang, John P. Lehan, Ulf Griesmann, Guangjun Gao
In characterizing the performance of a phase-shifting interferometer, the dependence of the measured height on the spatial frequency is rarely considered. We describe a test mirror with a special height relief that can be used to measure the height t ...
17. Stationary and non-stationary deformations in three-flat tests
Ulf Griesmann, Quandou Wang, Nicolas Laurenchet, Johannes A Soons
Calibration procedures for optical reference flats of phase-shifting interferometers (three-flat tests) are critically important if flatness measurements with low uncertainty are desired. In these tests, all combinations of three flats with unknown f ...
18. Dual-CGH Interferometry Test for X-Ray Mirror Mandrels
Guangjun Gao, John Lehan, Ulf Griesmann
We describe a glancing-incidence interferometric double-pass test, based on a pair of computer generated holograms (CGHs), for mandrels used to fabricate x-ray mirrors for space-based x-ray telescopes. The design of the test and its realization are d ...
19. Three-Flat Test Solutions Including Mounting-Induced Deformations
Ulf Griesmann, Quandou Wang, Johannes A Soons
We investigate three-flat calibration methods for circular flats, based on rotation symmetry and mirror symmetry, for absolute interferometric flatness measurements in the presence of deformations caused by the support mechanism for the flats, which ...
20. Manufacture and Metrology of 300 mm Silicon Wafers with Ultra-Low Thickness Variations
Ulf Griesmann, Quandou Wang, Marc Tricard, Paul Dumas, Christopher Hill
With the evolution of exposure tools for optical lithography towards larger numerical apertures, the semiconductor industry expects continued demand for improved wafer flatness at the exposure site. The Allowable site flatness for 300 mm wafers is ex ...