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Search Publications by: Ulf Griesmann (Fed)

Displaying 26 - 50 of 123

Figure metrology for x-ray focusing mirrors with Fresnel holograms and photon sieves

June 20, 2014

Author(s)

Ulf Griesmann, Johannes A. Soons, Quandou (. Wang, Lahsen Assoufid

We report on interferometric measurements of the figure error of an ultra-precise mirror with the shape of an elliptical toroid for the diffraction limited focusing of hard x-rays from an undulator x-ray source. We describe measurement configurations using

A versatile bilayer resist for laser lithography at 405 nm on glass substrates

October 23, 2013

Author(s)

Quandou (. Wang, Ulf Griesmann

We describe a simple bilayer photoresist that is particularly well suited for laser lithography at an exposure wavelength of 405 nm on glass substrates, which is often used for the fabrication of binary diffractive optics and computer generated holograms

Holographic Radius Test Plates

September 7, 2013

Author(s)

Quandou (. Wang, Johannes A. Soons, Ulf Griesmann

We evaluate a method for testing the radius of spheres with a hologram that consists of a pair of nested Fresnel zone lenses. The hologram is positioned in the collimated test beam of a Fizeau interferometer. The inner zone lens generates a focus at the

Absolute interferometric tests of spherical surfaces based on rotational and translational shears

September 13, 2012

Author(s)

Johannes A. Soons, Ulf Griesmann

Traceability of interferometric form measurements requires characterization of the reference wavefront. We investigate absolute tests for spherical surfaces where the form errors of both reference and test surface are estimated by minimizing the difference

Calibrating the sag due to gravity of horizontal interferometer reference flats

September 13, 2012

Author(s)

Ulf Griesmann, Jan Burke

We describe a method for measuring the deflection due to gravity (sag) of horizontally mounted reference flats of phase shifting interferometers. The planarity of a test flat can be measured sag- free while supporting it iso-statically on a suitable visco

Measurement of the diameter variation and refractive index inhomogeneity of a fused silica sphere using four-surface phase-shifting interferometry

September 9, 2012

Author(s)

Chu-Shik Kang, Ulf Griesmann, Johannes A. Soons

The diameter variation and refractive index inhomogeneity of a fused silica sphere were measured with a frequency-shifting Fizeau interferometer in a four-surface configuration. The phase-shifting algorithms to analyze the interference signals for each

Phase-shifting algorithms for the interferometric measurement of form error, diameter variation and refractive index inhomogeneity of fused silica spheres

September 9, 2012

Author(s)

Chu-Shik Kang, Ulf Griesmann, Johannes A. Soons

High-precision spheres have many applications in precision engineering and metrology, such as the calibration of transmission spheres for interferometry, density standards for mass metrology, and spherical gyroscope rotors. For these applications it is

A modified Roberts-Langenbeck test for measuring thickness and refractive index variation of silicon wafers

August 17, 2012

Author(s)

Jungjae Park, Lingfeng Chen, Quandou (. Wang, Ulf Griesmann

We describe a method to simultaneously measure thickness variation and refractive index homogeneity of 300 mm diameter silicon wafers using a wavelength shifting Fizeau interferometer operating at 1550 nm. Only three measurements are required

Plasma Etching Uniformity Control for Making Large and Thick Dual-Focus Zone Plates

August 1, 2011

Author(s)

Lei Chen, Quandou (. Wang, Ulf Griesmann

A typical zone plate structure is composed of concentric rings with a radially decreasing feature size such that the path of light through every second zone to the focus differs by one optical wavelength. In order to achieve the highest possible

Binary amplitude holograms made from dyed photoresist

May 13, 2011

Author(s)

Quandou (. Wang, Ulf Griesmann, John H. Burnett

A method for fabricating binary amplitude holograms from a dyed photoresist is described. It is of particular interest for holograms that are used as null lenses in the form metrology of aspheric surfaces and wavefronts. A pigment that strongly absorbs

Plasma Etching Uniformity Control for Making Large and Thick Dual-Focus Zone Plates

January 11, 2011

Author(s)

Lei Chen, Quandou (. Wang, Ulf Griesmann

In summary, an optimized plasma etching process has been developed and a Teflon ring has been made to minimize the feature size variation effect and eliminate the thick glass edge effect. Large phase type dual-focus zone plate with good etching profile and

Spatially resolved height response of phase-shifting interferometers measured using a patterned mirror with varying spatial frequency

September 1, 2010

Author(s)

JiYoung Chu, Quandou (. Wang, John Lehan, Ulf Griesmann

In the performance evaluation of phase-shifting interferometers for figure metrology, the height response, or height transfer function, is rarely taken into consideration, because in most applications smooth surfaces are measured and only the lowest

Flatness measurements of thin, plane-parallel optics floated on a heavy liquid

June 23, 2010

Author(s)

Ulf Griesmann, Quandou (. Wang, Eric C. Benck, Jiyoung Chu, Jaewoong Sohn

no abstract