Berlin 2014 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 32: Poster: Quantum gases, ultracold atoms and molecules
Q 32.87: Poster
Mittwoch, 19. März 2014, 16:30–18:30, Spree-Palais
Ultra stable laser system for two color photoassociation of Ca — •Max Kahmann1, Evgenij Pachomow1, Uwe Sterr1, Fritz Riehle1, and Eberhard Tiemann2 — 1Physikalisch Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig — 2Institut für Quantenoptik, Welfengarten 1, 30167 Hannover
For manipulating the scattering length by optical Feshbach resonances (OFR) the small linewidth of 40Ca (374 Hz) is expected to reduce the corresponding losses compared to the experiments with Yb and Sr [1]. We recently measured the binding energies of the least bound molecular states in the relevant molecular potentials [2]. These measurements and a derived coupled channel model for the atom pair asymptote 1S0+3P1 indicate 40Ca as a promising candidate for OFRs.
A variation of the scattering length by an OFR through a strong laser can be detected using a second laser for photoassociation to a more weakly bound state that probes the scattering wave function at larger atomic distances. The background scattering length can be determined by two-colour photoassociation spectroscopy of the least bound states in the ground state molecular potential applying the two ultra-stable lasers. For these experiments two phase-locked ultra stable spectroscopy lasers were set up. As a first test we have applied the lasers for Bragg spectroscopy of the trapped atoms.
This work was funded by DFG through QUEST and RTG 1729.
[1] R. Ciurylo, E. Tiesinga, P. Julienne, PRA 71, 030701 (2005)
[2] M. Kahmann et al, arXiv:1306.6473 (2013)