Surface profile measurement using spatially dispersed short coherence interferometry

Mothana A. Hassan, Haydn Martin, Xiangqian Jiang

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Improved online techniques for surface profile measurement can be beneficial in high/ultra-precision manufacturing, in terms of enabling manufacture and reducing costs. This paper introduces a spatially dispersed short-coherence interferometer sourced by a super luminescent diode. This technique uses a broadband light source, which is spatially dispersed across a surface using a reflective grating and a scan lens. In this way, the phase data pertaining to surface at height is spectrally encoded. The light reflected from the surface is interfered with a reference beam in a Michelson interferometer, after which the resulting fringes are interrogated by a spectrometer. Phase shifting interferometry is used to extract the spectrally encoded phase information by analysing four captured frames using a Carré algorithm procedure; in this way, surface height can be determined across a profile on a sample. The short coherent light utilized in this interferometric technique means it has the potential for an application as a remote probe through an optical fibre link. This paper describes the concept of a spatially dispersed short coherence interferometer and provides some of the initial experimental results.

Original languageEnglish
Article numbere024001
JournalSurface Topography: Metrology and Properties
Volume2
Issue number2
DOIs
Publication statusPublished - 1 Apr 2014

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