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Q: Fachverband Quantenoptik und Photonik
Q 29: Poster I
Q 29.7: Poster
Tuesday, March 3, 2009, 16:30–19:00, VMP 8 Foyer
A clock laser system for a Yb optical lattice atomic clock — •U. Bressel, A. Yu. Nevsky, S. Vasilyev, I. Ernsting, and S. Schiller — Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf
Neutral Ytterbium is a promising candidate for a lattice optical clock [1] with a potential accuracy exceeding that of the caesium microwave clock. 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 of 10−16. To interrogate such a narrow transition, a laser source with a sub-Hz linewidth should be developed. We have developed a clock laser based on frequency doubling (SHG) a grating-stabilized quantum-dot laser [2] at 1156 nm using a PPLN crystal in an external enhancement cavity. With 32 mW at 1156 nm the power at 578 nm is about 3.2 mW. As an alternative, a PPLN waveguide has been used with an output of 0,190 mW at 578 nm. In order to reduce the laser linewidth, the laser is being stabilized to a vibration-insensitive ULE reference cavity. It exhibits a finesse of 330 000 (4.5 kHz linewidth) at 578 nm and zero thermal expansion at 20∘C. The cavity is placed in a compact vacuum chamber with a dual-layer temperature stabilization system and mounted on active vibration isolation supports. Spectroscopy of the 171Yb clock transition 1S0 → 3P0 at 578 nm has been performed, yielding to an observation of the clock transition shifted 315 kHz to the expected value due to systematic effects.
[1] C. W. Hoyt et al., Phys. Rev. Lett. 95, 0303 (2005)
[2] A. Yu. Nevsky et al., Appl. Phys. B 92, 501-507, (2008)