Düsseldorf 2007 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 10: Poster I - Precisions Spectroscopy
A 10.10: Poster
Dienstag, 20. März 2007, 16:30–18:30, Poster B
A clock laser system for Yb optical frequency standard — •U. Bressel1, M. Okhapkin1,2, A.Yu. Nevsky1, and S. Schiller1 — 1Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf — 2Institute of Laser Physics, Novosibirsk
Ytterbium is a promising candidate for a lattice optical clock [1] with a potential accuracy significantly exceeding that of the best caesium clocks. The 1S0 - 3P0 clock transition at 578 nm is dipole forbidden and has a natural linewidth of about 10 mHz, leading to a transition Q-factor about 10^-16. To interrogate such a narrow transition, a reliable laser source with a sub-Hz linewidth should be developed. In our experiment the radiation at 578 nm is obtained by summing the frequencies of the Nd:YAG laser at 1064 nm and a grating-stabilized diode laser at 1267 nm in the PPLN crystal, placed in the enhancement cavity. We use the ILP-500/30 Nd:YAG laser [2] with intra-cavity frequency doubling. It is locked to a Doppler-free resonance in the molecular iodine. The enhancement cavity is locked to the Nd:YAG laser using the Pound-Drever-Hall technique. The frequency of the diode laser is locked to the cavity, thus making the cavity resonant for both IR radiations and yielding a frequency stability on the level of that of the Nd:YAG/I2 system. With 300 mW at 1064 nm and 20 mW at 1267 nm, the power at 578 nm is about 12 mW. The properties of the 578 nm radiation were characterized and work is in progress to stabilize this radiation to a high-finesse ULE cavity in order to reduce its linewidth.
[1] C.W. Hoyt et al, Phys. Rev. Lett. 95, 083003 (2005)
[2] see http://www.laser.nsc.ru/develop.htm