Hannover 2010 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 43: Ultracold Molecules (with MO)

Q 43.2: Talk

Thursday, March 11, 2010, 11:00–11:15, E 001

Enhancement of Photoassociation to Create Ultracold Molecules — •Ruzin Aganoglu, Mamadou Ndong, and Christiane Pia Koch — Institut für Theoretische Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin

Ultracold molecules can be created coherently by shaped ultrashort laser pulses. Since the broad bandwidth of femtosecond pulses addresses both atomic and molecular transitions and atomic excitation leads to trap loss, the spectral amplitude of the pulse at the atomic resonance frequency needs to be completely suppressed. This is most easily achieved by cutting off the pulse amplitude at the atomic resonance frequency and higher spectral components [1]. However the process leaves then most of the pulse idle. Here a two-photon photoassociation scheme is suggested to drive the desired narrow transition with a broad-band laser. Local control theory is used to define conditions on the pulse such that atomic transitions stay dark while molecular transitions are excited. Moreover to increase the initial pair density at inter-nuclear distances where the photoassociation probability is high, the concept of non-resonant field control [2] is combined with shape resonances. [1] A. Merli et al., Phys. Rev. A 80, 063417 (2009) [2] M. Lemeshko and B. Friedrich, Phys. Rev. Lett. 103, 053003 (2009)