Hannover 2010 – scientific programme

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MO: Fachverband Molekülphysik

MO 19: Ultracold Molecules (with Q)

MO 19.5: Talk

Thursday, March 11, 2010, 11:45–12:00, E 001

All Optical Rovibrational Ground State Preparation of HD⁺-Ions — •Tobias Schneider, Bernhard Roth, Hannes Duncker, Michael Hansen, Ingo Ernsting, and Stephan Schiller — Heinrich-Heine Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf

One important prerequisite for quantum measurements on molecules is the ability to control their translational as well as internal degrees of freedom. For molecular ions stored in an ion trap the motion of the molecules can be cooled via sympathetic cooling with laser cooled atomic ions. Cooling of the internal degrees of freedom is more difficult since in non-cryogenic environments interaction with black body radiation will generally distribute the molecular population over several ro-vibrational states.

We present a two laser optical pumping scheme suitable in principle for many types of diatomic molecules that allows to transfer most molecules to the ro-vibrational ground state. As a demonstration we apply the scheme HD⁺ molecular ions: Optically pumping with two cw lasers driving the (v=0,N=2)→(v=1,N=1) transition at 5484 nm and the (v=0,N=1)→(v=2,N=0) transition at 2713 nm of the electronic ground state, we increase the fractional ground state population from 10% to 78(4)% which is close to the maximum of 92% predicted by numerical simulations for a room temperature environment. A detailed analysis of the experiment and of the theoretical modelling of the pumping scheme will be given.