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Proceedings Paper

Absolute position sensor using Gaussian beam propagation properties and their spatial modulation
Author(s): Darine Haddad; Patrick Juncar; Gérard Genevès; Patrick Pinot
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Paper Abstract

Authors propose a new approach in displacement measurements based on Gaussian beam propagation, their focusing properties and their spatial modulation. Two modulated Gaussian beams with a phase shift of 180° are focused on a slit fixed to the moveable object. The resulting laser beams at the slit output are focused into a multimode fiber. A lock-in amplifier demodulates the photodiode signal placed at the multimode fiber output. The lock in-amplifier output signal is a function of the slit displacement. The sensor is completely fibered with no electrical wires so it presents no heat dissipation near the moveable object and is compatible with vacuum use. It is a contactless sensor and provides a simple compact design and cost-effective means of achieving high resolution absolute displacement measurements. The preliminary experimental data of the sensor calibration by laser interferometry have shown a resolution of 0.1 nm.

Paper Details

Date Published: 31 May 2007
PDF: 7 pages
Proc. SPIE 6585, Optical Sensing Technology and Applications, 65850U (31 May 2007); doi: 10.1117/12.723033
Show Author Affiliations
Darine Haddad, Lab. national de métrologie et d'essais (France)
Patrick Juncar, Conservatoire national des arts et métiers (France)
Gérard Genevès, Lab. national de métrologie et d'essais (France)
Patrick Pinot, Conservatoire national des arts et métiers (France)

Published in SPIE Proceedings Vol. 6585:
Optical Sensing Technology and Applications
Francesco Baldini; Jiri Homola; Robert A. Lieberman; Miroslav Miler, Editor(s)

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