Abstract
Chromatic dispersion is a fundamental optical property of materials related to physical quantities such ad density and chemical composition. The dispersion can be measured by multi-wavelength interferometry which is more robust compared with single wavelength interferometry since common-phase noise, e.g., optical path length fluctuations, are efficiently compensated. Therefore, a sensitive and fast method to measure dispersion with high spatial resolution would be a very efficient and robust tool in metrology, diagnostics, and industrial inspection. A simple, yet very effective and sensitive, method to exploit dispersion is the use of the so-called second-harmonic interferometer (SHI), which is a fully common-path two-color interferometer [1]. In a SHI the fundamental and second-harmonic beams co-propagate through the sample, then the fundamental beam is frequency doubled again, and finally the two second-harmonic beams interfere. The phase shift measured by the SHI is 4π/λ ∫L ∆n dl, where ∆n = n(λ/2)−n(λ), and L is the geometrical path between the two harmonic converters. The use of a single laser source greatly simplifies the set-up and the optical design compared to typical multi-wavelength interferometers, for an easy implementation also in industrial environments. Recently, high sensitivity SHI have been used to measure electron density in large plasma machines [2], and gas density in pulsed jet [3].
© 2013 IEEE
PDF ArticleMore Like This
Douglas J. Bamford, Elizabeth A. Cummings, Dmitriy Panasenko, David B. Fenner, Joel M. Hensley, Rejean L. Boivin, Thomas N. Carlstrom, and Michael A. Van Zeeland
CW3B.5 CLEO: Science and Innovations (CLEO:S&I) 2013
S. A. Rinehart, D. T. Leisawitz, D. Benford, D. Fixsen, M. Rizzo, M. Jackson, E. Mentzell, and R. Silverberg
FM2D.3 Fourier Transform Spectroscopy (FTS) 2013
Noel-Ivan Toto-Arellano, David Serrano-García, Luis García-Lechuga, Marcelo Miranda Gómez, German Resendiz López, and Angelina González Rosas
JTu4A.31 Adaptive Optics: Methods, Analysis and Applications (AO) 2013