Hannover 2020 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 13: Posters: Quantum Optics and Photonics I
Q 13.21: Poster
Monday, March 9, 2020, 16:30–18:30, Empore Lichthof
Improved Laser System for Optical Trapping of Neutral Mercury — •Rudolf Homm, Daniel Preißler, and Thomas Walther — Technische Universität Darmstadt, Institut für Angewandte Physik, Laser und Quantenoptik, Schlossgartenstraße 7, 64289 Darmstadt
Cold Hg-atoms in a magneto-optical trap offer opportunities for various experiments. The two stable fermionic isotopes are interesting with regard to a new time standard based on an optical lattice clock employing the 1S0 - 3P0 transition at 265.6 nm. The five stable bosonic isotopes can be used to form ultra cold Hg-dimers through photo-association in connection with vibrational cooling by applying a specific excitation scheme.
The laser system consists of an ECDL at 1014.8 nm followed by a Yb-fiber amplifier and two consecutive frequency-doubling stages. Due to a 50W-pumplaser at 976 nm the power of the ECDL was amplified to about 12 W. This results in about 5 W at 507.4 nm after the first frequency-doubling cavity.
The limiting factor in generating high power at 253.7 nm so far, was the degradation of the non-linear BBO-crystal used in the second frequency-doubling stage. To avoid this problem, we developed a cavity with elliptical focusing [1], which was already successfully tested in other laser systems [2]. Our goal is to replace the actual cavity with one with elliptical focusing to reach higher power at 253.7 nm without degradation. We will report on the status of the experiments.
[1] Preißler, D., et al., Applied Physics B 125 (2019): 220
[2] Kiefer, D., et al., Laser Physics Letters 16 (2019): 075403