1. Non-contact XUV metrology of Ru/B 4 C multilayer optics by means of Hartmann wavefront analysis
- Author
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Lu Li, Hugo Dacasa, Magali Lozano, Davide Bleiner, Mabel Ruiz-Lopez, Benoît Mahieu, Philippe Zeitoun, Swiss Federal Laboratories for Materials Science and Technology [Dübendorf] (EMPA), Deutsches Elektronen-Synchrotron [Hamburg] (DESY), Laboratoire d'optique appliquée (LOA), and École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Physics - Instrumentation and Detectors ,Materials science ,FOS: Physical sciences ,01 natural sciences ,010309 optics ,Optics ,0103 physical sciences ,High harmonic generation ,Electrical and Electronic Engineering ,Engineering (miscellaneous) ,Lithography ,ComputingMilieux_MISCELLANEOUS ,010302 applied physics ,Wavefront ,[PHYS]Physics [physics] ,[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics] ,business.industry ,Instrumentation and Detectors (physics.ins-det) ,Wavefront sensor ,Atomic and Molecular Physics, and Optics ,Metrology ,Wavelength ,Extreme ultraviolet ,Reflection (physics) ,business ,Optics (physics.optics) ,Physics - Optics - Abstract
Short-wavelength imaging, spectroscopy, and lithography scale down the characteristic length-scale to nano meters. This poses tight constraints on the optics finishing tolerances, which is often difficult to characterize. Indeed, even a tiny surface defect degrades the reflectivity and spatial projection of such optics. In this study, we demonstrate experimentally that a Hartmann wavefront sensor for extreme ultraviolet (XUV) wavelengths is an effective non-contact analytical method for inspecting the surface of multilayer optics. The experiment was carried out in a tabletop laboratory using a high-order harmonic generation as an XUV source. The wavefront sensor was used to measure the wavefront errors after the reflection of the XUV beam on a spherical Ru/B4C multilayer mirror, scanning a large surface of approximately 40 mm in diameter. The results showed that the technique detects the aberrations in the nanometer range., 6 pages, 4 figures
- Published
- 2018