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Search Publications by: Ulf Griesmann (Fed)

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Displaying 51 - 75 of 123

Power Spectral Density: Is it right?

June 13, 2010
Author(s)
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 for PSD

Computer-Generated Hologram Cavity Interferometry Test for Large X-Ray Mandrels: Design

June 1, 2009
Author(s)
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 incidence

Index of Retraction and its Temperature Dependence of Calcium Fluoride Near 157nm

October 16, 2008
Author(s)
John H. Burnett, Ulf Griesmann, R Gupta, T E. Jou
We have made accurate measurements near 157 nm of the relative index of refraction, its dispersion, and its temperature dependence for two grades of calcium fluoride in N 2 gas. Accurate measurements of the quantitites are needed for the design of lens

Measuring the Phase Transfer Function of a Phase-Shifting Interferometer

August 13, 2008
Author(s)
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

Stationary and non-stationary deformations in three-flat tests

July 7, 2008
Author(s)
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

Dual-CGH Interferometry Test for X-Ray Mirror Mandrels

June 15, 2008
Author(s)
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

Three-Flat Test Solutions Including Mounting-Induced Deformations

September 1, 2007
Author(s)
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 are a