Berlin 2014 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 34: Poster: Ultra-cold atoms, ions and BEC (with Q)
A 34.27: Poster
Mittwoch, 19. März 2014, 16:30–18:30, Spree-Palais
Narrow-line laser cooling of dysprosium into an optical dipole trap — •Matthias Schmitt, Thomas Maier, Holger Kadau, Axel Griesmaier, and Tilman Pfau — 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
We present our techniques to laser cool dysprosium on a narrow-line transition to achieve suitable conditions to directly load atoms into an optical dipole trap. Dysprosium is the element with the highest magnetic moment and offers a non-spherical symmetric groundstate 5I8. This complex electronic structure leads to several possible cooling and optical pumping transitions. We use a broad cooling transition at 421 nm for Zeeman slowing and capture these atoms in a narrow-line magneto-optical trap using a transition at 626 nm. A transversal cooling stage before the Zeeman slower increases the capture rate by a factor of 4 and atom number by a factor of 3. By using a spectral broadener to increase the capture velocity, we can trap up to 1.2 · 108 atoms and double the capture rate.
To directly load into an optical dipole trap, we compress the magneto optical trap and achieve temperatures of ∼ 10 µ K. We transfer 10 million atoms and subsequently optically transport the cold atom cloud to a glass cell, which offers high optical access. Ongoing work is to increase the phase space density until quantum degeneracy in a crossed optical dipole trap. Future techniques are to implement a high resolution imaging and the possibility to write nearly arbitrary time-averaged potentials with an electro-optical deflector system.