High-accuracy absolute distance measurement with a mode-resolved optical frequency comb

High-accuracy absolute distance measurement with a mode-resolved optical frequency comb

Voigt, Dirk (VSL Dutch Metrology Institute)
Van Den Berg, Steven A. (VSL Dutch Metrology Institute)
Lešundák, Adam (Institute of Scientific Instruments AS CR V.v.i)
van Eldik, S. (MAPPER Lithography)
Bhattacharya, N. (TU Delft ImPhys/Optics)

Berghmans, Francis (editor)
Mignani, Anna G. (editor)

2016

Optical interferometry enables highly accurate non-contact displacement measurement. The optical phase ambiguity needs to be resolved for absolute distance ranging. In controlled laboratory conditions and for short distances it is possible to track a non-interrupted displacement from a reference position to a remote target. With large distances covered in field applications this may not be feasible, e.g. in structure monitoring, large scale industrial manufacturing or aerospace navigation and attitude control. We use an optical frequency comb source to explore absolute distance measurement by means of a combined spectral and multi-wavelength homodyne interferometry. This relaxes the absolute distance ambiguity to a few tens of centimeters, covered by simpler electronic distance meters, while maintaining highly accurate optical phase measuring capability. A virtually imaged phased array spectrometer records a spatially dispersed interferogram in a single exposure and allows for resolving the modes of our near infrared comb source with 1 GHz mode separation. This enables measurements with direct traceability of the atomic clock referenced comb source. We observed agreement within 500 nm in comparison with a commercial displacement interferometer for target distances up to 50 m. Furthermore, we report on current work toward applicability in less controlled conditions. A filter cavity decimates the comb source to an increased mode separation larger than 20 GHz. A simple grating spectrometer then allows to record mode-resolved interferograms.

distance measurement
frequency mode filter
laser ranging
measurement uncertainty
optical frequency comb
optical metrology
spectral interferometry
traceability

http://resolver.tudelft.nl/uuid:f95abe82-88d2-4e33-af4c-cec4267ebf50

https://doi.org/10.1117/12.2227360

SPIE

978-1-510601444

Optical Sensing and Detection IV, 9899

Optical Sensing and Detection IV, 2016-04-03 → 2016-04-07, Brussels, Belgium

Proceedings of SPIE, 0277-786X, 9899

Institutional Repository

conference paper

© 2016 Dirk Voigt, Steven A. Van Den Berg, Adam Lešundák, S. van Eldik, N. Bhattacharya