Absolute thickness metrology with high precision using low coherence interferometry

Yang Zhao, Greg Schmidt, Duncan T. Moore, Jonathan D. Ellis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In refractive index profile measurement for gradient index (GRIN) materials which have designed inhomogeneous refractive index, sample thickness variations across the aperture are required to be measured to obtain accurate index profiles. In this work, instrumentation was developed to measure the absolute thickness map of samples with parallel specular surfaces up to 10 mm thick, with the ability to measure the surface figure of both sides. Using this system, we are able to measure absolute sample thickness currently accurate to sub micrometer levels, based on the short coherence length of the light source. Besides gradient index materials, this method is also potentially capable of measuring other inhomogeneous and opaque materials.

Original languageEnglish (US)
Title of host publicationProceedings - ASPE 2014 Annual Meeting
PublisherAmerican Society for Precision Engineering, ASPE
Pages417-421
Number of pages5
ISBN (Electronic)9781887706667
StatePublished - 2014
Externally publishedYes
Event29th Annual Meeting of the American Society for Precision Engineering, ASPE 2014 - Boston, United States
Duration: Nov 9 2014Nov 14 2014

Publication series

NameProceedings - ASPE 2014 Annual Meeting

Conference

Conference29th Annual Meeting of the American Society for Precision Engineering, ASPE 2014
Country/TerritoryUnited States
CityBoston
Period11/9/1411/14/14

ASJC Scopus subject areas

  • Engineering(all)

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