Many-wavelength interferometry with thousands of lasers for absolute distance measurement.
We demonstrate a new technique for absolute distance measurement with a femtosecond frequency comb laser, based on unraveling the output of an interferometer to distinct comb modes with 1 GHz spacing. From the fringe patterns that are captured with a camera, a distance is derived by combining spectral and homodyne interferometry, exploiting about 9000 continuous wave lasers. This results in a measurement accuracy far within an optical fringe (λ/30), combined with a large range of nonambiguity (15 cm). Our technique merges multiwavelength interferometry and spectral interferometry, within a single scheme.
National Metrology Institute VSL, Thijsseweg 11, 2629 JA Delft, The Netherlands. svdberg@vsl.nl
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van den Berg
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Persijn
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Kok
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Zeitouny
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Bhattacharya