Efficient creation of translational cold heteronuclear dimers in the rovibrational ground state from ultracold atoms via photoassociation followed by optical pumping
Final Report Abstract
My proposed project was to create a sample of polar RbCs molecules in the rovibrational ground state trapped in an optical lattice. An experiment at Yale University led by David DeMille is hoping to use such molecules for a quantum register where q-bits are to be realized by single molecules and are going to interact via the dipole interaction induced by an electric field. Recently, they have shown that they are able to form RbCs molecules in photoassociation with a cw laser, trap those dimers in highly excited, non-polar levels in an optical lattice, and detect those in a REMPI scheme with pulsed lasers. My aim was to transfer of the photoassociated molecules into the absolute ground state. For this, we were trying to realize a lambda scheme with two diode lasers that is similar to previous experiments with pulsed lasers but allows for the spectral resolution of rotational lines. The two needed diode lasers systems have been set up. Their powers after an amplification stage, their linewidth, their long-term frequency stability from an offset-lock, and the characteristics of light pulses created with AOMs have been measured. All requirements for the experiment are met. Sadly, the production of RbCs molecules in photoassociation, i.e., the starting point of the proposed transfer, did not work properly: Getters had been used as a source but did run empty in the preceding experiments. Temperature controlled reservoirs of Rb and Cs allowed us to create dense traps of both Rb and Cs by loading from the background gas. However, atoms accumulated on the viewports reacted with viewports for the CO2 laser and most of the trapping light got absorbed. The switch to the cold reservoirs did not pay off since an essential ingredient of the proposed experiments, namely the optical lattice, does not work in these conditions.
Publications
- Potassium ground state scattering parameters and Born-Oppenheimer potentials from molecular spectroscopy, International Conference on Atomic Physics, Storrs, CT (2008)
St. Falke, H. Knöckel, J. Friebe, M. Riedmann, E. Tiemann, Ch. Lisdat
- Ultracold Production and Trapping of Ultracold RbCs Molecules, International Conference on Atomic Physics, Storrs, CT (2008)
Eric R. Hudson, Nathan B. Gilfoy, Stephan Falke, C.D. Bruzewicz, S. Kotochigova, and D. DeMille
- Toward Trapped Ultracold Molecules in the Absolute Ground State, DAMOP, Charlottesville, VA (2009)
Nathan Gilfoy, Stephan Falke, Colin Bruzewicz, Eric Hudson, and David DeMille
