Temperature stabilization of semiconductor lasers for direct measurement of index of refraction of air

0205697 - UPT-D 20030080 RIV CZ eng C - Conference Paper (international conference)
Matoušek, Vít
Temperature stabilization of semiconductor lasers for direct measurement of index of refraction of air.
Proceedings of the International Conference and Competition Student EEICT 2003. Brno: Brno University of Technology, 2003 - (Řezáč, D.; Zacios, D.), s. 189 - 193. ISBN 80-214-2401-X.
[STUDENT EEICT 2003. Brno (CZ), 24.04.2003]
R&D Projects: GA ČR GP102/02/P122; GA ČR GA102/02/1318
Institutional research plan: CEZ:AV0Z2065902
Keywords : laser interferometers * temperature stabilization * refraction
Subject RIV: BH - Optics, Masers, Lasers

Laser interferometers are even more precise distance measurement devices with resolution in nanometer or sub-nanometer region. If interferometric measurements are carried out under atmospheric conditions (usual situation in industry), they measure optical path length of an unknown distance instead of its true geometrical value. It is caused by an index of refraction of air that introduces a multiplicative constant to measured results. If we want to obtain correct values, the knowledge of the index of refraction is necessary. Generally, the index of refraction can be measured by two ways: indirectly or directly. The first of them is based on parametric analysis of atmospheric properties as: relative humidity, pressure, temperature, concentration of CO₂ etc. Values of these parameters are processed then by Edlen formulas with 10^-7 order [1]. The direct methods are more precise then Edlen formulas (more than 10^-7) but their practical implementation is more difficult. Devices that directly measure the index of refraction are called refractometers.
Permanent Link: http://hdl.handle.net/11104/0101310