Two wavelength microscopic TV interferometric system for surface profiling

U. Paul Kumar, Basanta Bhaduri, N. Krishna Mohan, M. P. Kothiyal

Abstract

Non-contact techniques for rapid and accurate mapping of micro-machined surfaces are important for the optoelectronic industry. Interferometry is an important tool for precision metrology of surfaces. It has been used for applications such as surface profiling, roughness measurement and quality testing of optical elements. The singlewavelength conventional interferometry can handle the smoothly varying surface profiles and step-heights less than half a wavelength. In this paper we describe a two wavelength microscopic TV interferometric system which removes ambiguity associated with the single wavelength data and also extends the phase measurement range compared to the conventional single wavelength interferometry. The results obtained using this two wavelength microscopic system for 3D surface profiling on smooth specimens are presented.

Keywords

Two wavelength microscopic TV interferometry; phase reversal subtraction technique; phase shifting; surface profiling; fringe analysis

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IMEKO-TC14-2007-15.pdf

DOI

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IMEKO TC

TC14 - Measurement of Geometrical Quantities

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