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Proceedings Paper

White light phase shifting interferometry and color fringe analysis for the detection of contaminants in water
Author(s): Vishesh Dubey; Veena Singh; Azeem Ahmad; Gyanendra Singh; Dalip Singh Mehta
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Paper Abstract

We report white light phase shifting interferometry in conjunction with color fringe analysis for the detection of contaminants in water such as Escherichia coli (E.coli), Campylobacter coli and Bacillus cereus. The experimental setup is based on a common path interferometer using Mirau interferometric objective lens. White light interferograms are recorded using a 3-chip color CCD camera based on prism technology. The 3-chip color camera have lesser color cross talk and better spatial resolution in comparison to single chip CCD camera. A piezo-electric transducer (PZT) phase shifter is fixed with the Mirau objective and they are attached with a conventional microscope. Five phase shifted white light interferograms are recorded by the 3-chip color CCD camera and each phase shifted interferogram is decomposed into the red, green and blue constituent colors, thus making three sets of five phase shifted intererograms for three different colors from a single set of white light interferogram. This makes the system less time consuming and have lesser effect due to surrounding environment. Initially 3D phase maps of the bacteria are reconstructed for red, green and blue wavelengths from these interferograms using MATLAB, from these phase maps we determines the refractive index (RI) of the bacteria. Experimental results of 3D shape measurement and RI at multiple wavelengths will be presented. These results might find applications for detection of contaminants in water without using any chemical processing and fluorescent dyes.

Paper Details

Date Published: 9 March 2016
PDF: 7 pages
Proc. SPIE 9718, Quantitative Phase Imaging II, 97181F (9 March 2016); doi: 10.1117/12.2212405
Show Author Affiliations
Vishesh Dubey, Indian Institute of Technology Delhi (India)
Veena Singh, Indian Institute of Technology Delhi (India)
Azeem Ahmad, Indian Institute of Technology Delhi (India)
Gyanendra Singh, Indian Institute of Technology Delhi (India)
Dalip Singh Mehta, Indian Institute of Technology Delhi (India)


Published in SPIE Proceedings Vol. 9718:
Quantitative Phase Imaging II
Gabriel Popescu; YongKeun Park, Editor(s)

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