Heidelberg 2015 – wissenschaftliches Programm
A 19.5: Vortrag
Mittwoch, 25. März 2015, 12:00–12:15, C/HSO
Frequency comb-based heterodyne many-wavelength interferometry — •Jutta Mildner, Karl Meiners-Hagen, and Florian Pollinger — Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig
Up-to-date long distance metrology in engineering, geodesy and surveying ask for relative measurement uncertainties of better than 10−7. A promising tool to push optical-based measurement techniques into this regime are broadband optical frequency combs. In this contribution we want to present a novel concept of a comb-based many-wavelength interferometer in which a direct heterodyne phase detection of individual comb lines is aimed at. To this end a single fiber-based optical frequency comb with CEO-stabilization is used as a seed laser. By cavity filtering two coherent combs of different mode spacing are generated and subsequently used as local oscillator and measurement beam. Based on this scheme, a complete chain of synthetic wavelengths from the optical to the microwave range can be realized in theory, making full phase unwrapping possible without additional high accuracy information. Development and demonstration of a prototype filtering unit with tunable spacing will be presented, including simulations and experiments on positioning sensitivity. Furthermore, we want to discuss the deployed stabilization schemes as well as current progress on optimization measures. This project is performed within the joint research project SIB60 ’Surveying’ of the European Metrology Research Programme (EMRP). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.