Jiang, Xiang, Wang, Kaiwei, Martin, Haydn and Yang, Shuming (2007) Surface characteristic determining apparatus. WO2007144654.
Metadata only available from this repository.Abstract
Light from the first and second different wavelength light sources is combined and supplied to a director that directs zeroth order light to a reference surface and other order, generally first order diffracted light to on a location of the sample surface which is dependent upon wavelength. Light reflected by the sample and reference surfaces interfere. A characteristic of a sample surface is determined from interference light of the first wavelength. Interference light of the second wavelength is used to enable phase-locking by adjusting the path length difference by moving the reference surface or changing the refractive index of a path portion to compensate for phase variation due to environmental effects.; Non- mechanical scanning is used to scan the sample surface by using a variable wavelength source and a director providing different first order diffraction angles for different wavelengths or an acousto-optical device that provides a variable pitch acoustic diffraction grating.
Item Type: | Patent |
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Subjects: | T Technology > TA Engineering (General). Civil engineering (General) |
Schools: | School of Computing and Engineering School of Computing and Engineering > Centre for Precision Technologies School of Computing and Engineering > Centre for Precision Technologies > Surface Metrology Group |
Related URLs: | |
Depositing User: | Cherry Edmunds |
Date Deposited: | 20 Nov 2008 15:18 |
Last Modified: | 28 Aug 2021 10:43 |
URI: | http://eprints.hud.ac.uk/id/eprint/2743 |
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