27 April 2018 Simultaneous distance measurement at multiple wavelengths using the intermode beats from a femtosecond laser coherent supercontinuum
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Abstract
The intermode beats generated by direct detection of a mode-locked femtosecond laser represent inherent high-quality and high-frequency modulations suitable for electro-optical distance measurement (EDM). This approach has already been demonstrated as a robust alternative to standard long-distance EDM techniques. However, we extend this idea to intermode beating of a wideband source obtained by spectral broadening of a femtosecond laser. We aim at establishing a technological basis for accurate and flexible multiwavelength distance measurement. Results are presented from experiments using beat notes at 1 GHz generated by two bandpass-filtered regions from both extremes of a coherent supercontinuum ranging from 550 to 1050 nm. The displacement measurements performed simultaneously on both colors on a short-distance setup show that noise and coherence of the wideband laser are adequate for achieving accuracies of about 0.01 mm on each channel with a potential improvement by accessing higher beat notes. Pointing and power instabilities have been identified as dominant sources of systematic deviations. Nevertheless, the results demonstrate the basic feasibility of the proposed technique. We consider this a promising starting point for the further development of multiwavelength EDM enabling increased accuracy over long distances through dispersion-based integral refractivity compensation and for remote surface material probing along with distance measurement in laser scanning.
© 2018 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2018/$25.00 © 2018 SPIE
David Salido-Monzú and Andreas Wieser "Simultaneous distance measurement at multiple wavelengths using the intermode beats from a femtosecond laser coherent supercontinuum," Optical Engineering 57(4), 044107 (27 April 2018). https://doi.org/10.1117/1.OE.57.4.044107
Received: 22 December 2017; Accepted: 2 April 2018; Published: 27 April 2018
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CITATIONS
Cited by 6 scholarly publications.
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KEYWORDS
Distance measurement

Sensors

Femtosecond phenomena

Optical engineering

Mode locking

Modulation

Refractive index

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