Coherence scanning interferometry (CSI) is any of a class of optical surface measurement methods wherein the localization of interference fringes during a scan of optical path length provides a means to determine surface characteristics such as topography, transparent film structure, and optical properties. CSI is currently the most common interference microscopy technique for areal surface topography measurement. The term "CSI" was adopted by the International Organization for Standardization (ISO).ISO (2013). 25178-604:2013(E): Geometrical product specification (GPS) – Surface texture: Areal – Nominal characteristics of non-contact (coherence scanning interferometric microscopy) instruments (2013(E) ed.). Geneva: International Organization for Standardization.
The technique encompasses but is not limited to instruments that use spectrally broadband, visible sources (white light) to achieve interference fringe localization. CSI uses either fringe localization alone or in combination with interference fringe phase, depending on the surface type, desired surface topography repeatability and software capabilities. The table below compiles alternative terms that conform at least in part to the above definition.
Acronym Term Reference CSI Coherence scanning interferometry CPM Coherence probe microscope CSM Coherence scanning microscope CR Coherence radar CCI Coherence correlation interferometry Lee-Bennett, I. (2004). Advances in non-contacting surface metrology. Optical Fabrication and Testing, OTuC1. MCM Mirau correlation microscope WLI White light interferometry WLSI White light scanning interferometry Wyant, J. C. (September, 1993). How to extend interferometry for rough-surface tests. Laser Focus World, 131-135. SWLI Scanning white light interferometry WLS White Light Scanner WLPSI White light phase-shifting interferometry VSI Vertical scanning interferometry RSP Rough surface profiler IRS Infrared scanning OCT Full-field optical coherence tomography
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