Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 45: Precision Measurement and Metrology 2
Q 45.6: Vortrag
Donnerstag, 17. März 2011, 12:00–12:15, HÜL 386
Frequency Combs for Calibration of High-Precision Astronomical Spectrographs — •Tobias Wilken1, Tilo Steinmetz1,2, Rafael Probst1, Ronald Holzwarth1,2, Theodor W. Hänsch1, and Thomas Udem1 — 1Max-Planck-Institut für Quantenoptik, Garching — 2Menlosystems GmbH, Martinsried
High precision spectrography in astronomy is at present limited by the available calibration sources. Frequency combs have have been proposed to be an optimal calibration source if they fulfill certain requirements with respect to their spectral bandwidth and mode spacing.
We have developed a frequency comb, based on an Yb-fiber laser which is filtered with Fabry-Perot cavities (FPCs) to have a mode spacing of >10 GHz. After frequency doubling the comb, ∼ 6 nm bandwidth at 526 nm are obtained and this comb was tested at the HARPS spectrograph in La Silla, Chile. This is to date the most precise instrument in the world. A calibration uncertainty limited by photon noise has been observed.
Currently we are working on broadening the optical spectrum to cover the bandwidth of the spectrograph. In this context, noise issues and the reamplification of modes which were initially suppressed by the FPCs need to be investigated in more detail. The latest results will be presented in this talk.