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1999
Conference Paper
Titel
Interferometric measurements of aspherical surfaces using automatically aligned nulltests and multiple wavelengths
Abstract
This paper discusses two closely related aspects in the field of interferometrical shape testing. First, current research work in the field of aspheric shape testing is presented. The measurement range that is limited especially if discontinous surfaces are inspected has been extended with the use of the so-called "Multiple Wavelength Interferometry". New experimental results are presented and the effect ofaberrations dur to strong surface slopes is discussed. Second, a nulltest is presented, which enables the measurement of aspheric mirrors with the use of a so-called "Hindie sphere". Here, especially the alignment of the complex set-up was the main point of investigation as it offers up to ten degrees of freedom and their alignment is a challenging issue. Together, inspection of ultra precision aspheric surfaces and alignment of the inspecting optical systems in order to decrease their systematic errors will be important fields of research during the next years.