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Updated: Jul 4, 2026

Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
Published on: March 22, 2019
Laboratory demonstration of an infrared-to-visible up-conversion interferometer for spatial coherence analysis
S Brustlein1, L Del Rio, A Tonello
1XLIM Département Photonique, UMR CNRS 6172, 123 Avenue A. Thomas, Limoges Cedex, France.
Abstract:
We experimentally demonstrate the possibility of retrieving the spatial coherence of an infrared source by using an up-conversion interferometer. Sum-frequency generation in Ti-diffused periodically poled lithium-niobate waveguides in both arms of the interferometer is used to convert the infrared into the visible domain. The fringe contrast of the interference pattern in the visible domain permits us to resolve the spatial separation of two uncorrelated pointlike infrared sources, which simulate a binary star. The validity of these measurements is confirmed through a simultaneous comparison with a reference interferometer working in the infrared domain.
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