Hannover 2013 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 20: Poster: Precision spectroscopy of atoms and ions (with Q)

A 20.9: Poster

Dienstag, 19. März 2013, 16:00–18:30, Empore Lichthof

Spectroscopy of a narrow-line optical pumping transition in atomic dysprosium — •Holger Kadau, Thomas Maier, Matthias Schmitt, Michaela Nickel, Axel Griesmaier, and Tilman Pfau — 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany

Dysprosium is a rare-earth element with a complex energy level structure with several possible cooling and optical pumping transitions. We have prepared samples of dysprosium atoms at ∼ 1  mK in a magneto-optical trap by laser cooling on a broad transition at 421   nm. One possibility to laser cool the atoms further is to use a narrow-line optical transition at 626   nm and reach conditions suitable for forced evaporative cooling in an optical dipole trap.

One alternative to forced evaporative cooling is lossless demagnetization cooling [1]. It requires an atomic sample with inelastic dipolar scattering in its lowest energetic state, a controllable magnetic field and an optical pumping transition. We present a suitable candidate for such optical pumping at a wavelength of 684   nm. We assign the positions of the so far unknown fermionic hyperfine shifts of the transition. We measured the transition linewidth and give an upper limit for the branching ratio between decay to the groundstate and other states. Our measurements show that this transition is usable for optical pumping and demagnetization cooling.

[1] M. Fattori et al., Nat. Phys. 2, 126401 (2006)