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arXiv · 2211.16013

Low coherence interferometric detection of the spectral dependence of the retro-reflection coefficient of an anti-reflective coated interface

Michel Lequime·Imran Khan·Myriam Zerrad·Claude Amra
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Abstract

The measurement of very low reflection coefficients of anti-reflective coated interfaces has become a key issue for the realization of precision instruments such as the giant interferometers used for the detection of gravitational waves. We propose in this paper a method, based on low coherence interferometry and balanced detection, which not only allows to obtain the spectral dependence of this reflection coefficient in amplitude and phase, with a sensitivity of the order of 0.1 ppm and a spectral resolution of 0.2 nm, but also to eliminate any spurious influence related to the possible presence of uncoated interfaces. This method also implements a data processing similar to that used in Fourier transform spectrometry. After establishing the formulas that control the accuracy and the signal-to-noise ratio of this method, we present the results that provide a complete demonstration of its successful operation in various experimental conditions.

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Michel Lequime, Imran Khan, Myriam Zerrad, Claude Amra. 2022-11-29. Low coherence interferometric detection of the spectral dependence of the retro-reflection coefficient of an anti-reflective coated interface. https://doi.org/10.1364/oe.481346

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