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Author: quandou wang
Displaying records 11 to 20 of 30 records.
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11. A Simple Method to Improve Etching Uniformity when Making Phase Type CGHs on a Thick Glass Substrate
A simple method to optimize the etching uniformity when making a Computer generated halogram on a thick optical glass substrate is described, which uses a Teflon ring to enclose the substrate during reactive-ion etching (RIE).
12. 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
13. 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 ...
14. 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 ...
15. 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 ...
16. 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 ...
17. 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 ...
18. Mini-Fizeau Interferometer for Curvature Sensing in the NIST Geometry Measuring Machine
Quandou Wang, Ulf Griesmann
We describe the design of a miniature Fizeau interferometer, which is intended to be an accurate curvature sensor for the NIST Geometry Measuring (GEMM), which is used to measure aspheric and free form surfaces. The interferometer was designed for s ...
19. A Tool Kit to Generate 3D Animated CAESAR Bodies
Quandou Wang, Sanford P Ressler
The Civilian American and European Surface Anthropometry Resource (CAESAR) database provides a comprehensive source for body measurement in numerous industries such as apparel, aerospace, and automobile. Generating animated CAESAR body sequences fro ...
20. Uncertainties in Aspheric Profile Measurements with the Geometry Measuring Machine at NIST
Ulf Griesmann, Nadia Machkour-Deshayes, Byoung Chang Kim, Quandou Wang, Lahsen Assoufid
The Geometry Measuring Machine (GEMM) of the National Institute of Standards and Technology (NIST) is a profilometer for free-form surfaces. A profile is reconstructed from local curvature of a test part surface, measured at several locations along ...