Displacement measurement with over-determined interferometer

0388095 - ÚPT 2013 RIV US eng C - Conference Paper (international conference)
Lazar, Josef - Holá, Miroslava - Hrabina, Jan - Buchta, Zdeněk - Číp, Ondřej - Oulehla, Jindřich
Displacement measurement with over-determined interferometer.
CPS 2012. 18th Czech-Polish-Slovak Optical Conference on Wave and Quantum Aspects of Contemporary Optics (Proceedings of SPIE Vol.8697). Bellingham: SPIE, 2012, 86970E:1-7. ISBN 978-0-8194-9481-8.
[CPS 2012. Czech-Polish-Slovak Optical Conference on Wave and Quantum Aspects of Contemporary Optics /18./. Ostravice (CZ), 03.09.2012-07.09.2012]
R&D Projects: GA ČR GA102/09/1276; GA ČR GPP102/11/P820; GA TA ČR TA02010711; GA TA ČR TE01020233; GA MŠMT ED0017/01/01
Institutional support: RVO:68081731
Keywords : Interferometers * Interferometry * Lasers * Refractive index * Zerodur
Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

We present a concept combining traditional displacement incremental interferometry with a tracking refractometer following the fluctuations of the refractive index of air. This concept is represented by an interferometric system of three Michelson-type interferometers where two are arranged in a counter-measuring configuration and the third one is set to measure the changes of the fixed length, here the measuring range of the overall displacement. In this configuration the two counter-measuring interferometers have identical beam paths with proportional parts of the overall one. The fixed interferometer with its geometrical length of the measuring beam linked to a mechanical reference made of a high thermal-stability material (Zerodur) operates as a tracking refractometer monitoring the atmospheric refractive index directly in the beam path of the displacement measuring interferometers. This principle has been demonstrated experimentally through a set of measurements in a temperature controlled environment under slowly changing refractive index of air in comparison with its indirect measurement through Edlen formula. With locking of the laser optical frequency to fixed value of the overall optical length the concept can operate as an interferometric system with compensation of the fluctuations of the refractive index of air.
Permanent Link: http://hdl.handle.net/11104/0216989