Hannover 2013 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 43: Poster II
Q 43.26: Poster
Wednesday, March 20, 2013, 16:00–18:30, Empore Lichthof
Spectroscopic in-situ traceability for absolute distance interferometry — Günther Prellinger, Karl Meiners-Hagen, and •Florian Pollinger — Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
A popular approach to absolute distance measurements with interferometric accuracy is the so-called variable synthetic wavelength interferometry. The absolute length is deduced by the analysis of the phase shift of an interferometer signal observed during a defined frequency variation of the laser source. The accuracy of this method depends, inter alia, on the knowledge of the frequency change. Usually, technical references like Fabry-Perot interferometers or calibrated reference interferometers are used. Their stability and accuracy limits the uncertainty of the method today, in particular for the application in non-cooperative environments. In the presented study, Doppler-free iodine absorption spectroscopy is applied to determine the frequency change. A high-speed spectroscopic detection system has been realised capable of measurement times below 10 µs per absorption line. Thus, in-situ spectroscopic monitoring of the spectroscopic frequency markers can be performed in parallel to the interferometric phase measurement. First experiments indicate an achievable relative uncertainty better than 5 × 10−9 for the position of the frequency markers.
The project is funded by the DFG under grant PO1560/1-1.