Darmstadt 2008 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

Q: Fachverband Quantenoptik und Photonik

Q 42: Ultrakalte Atome (Manipulation und Detektion / Quantengase)

Q 42.1: Group Report

Thursday, March 13, 2008, 14:00–14:30, 1C

Direct observation of individual atoms in an optical lattice — •Tatjana Gericke, Peter Würtz, Daniel Reitz, Tim Langen, and Herwig Ott — Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz

Ultracold atoms in optical lattices have demonstrated to be an interesting system to study quantum phenomena such as quantum phase transitions and strongly correlated many-body systems. The lattice spacing in such systems ranges from 400 nm to 600 nm. Although many different detection schemes have been developed, a high resolution in situ imaging system with single atom sensitivity is still lacking. Our new imaging technique is based on the principles of scanning electron microscopy in combination with electron impact ionization. A 6 keV electron beam with a FWHM of around 200 nm is scanned across the atom cloud and ionizes an atom. The resulting ion is subsequently extracted with the aid of ion optics and detected by a channeltron detector.

We use an all optical BEC approach in a single beam CO₂ optical dipole trap and produce a ⁸⁷Rb condensate with up to 120000 atoms. The condensate is then loaded into an optical lattice. The optical lattice has a spacing of 604 nm and is formed by two focused laser beams with a wavelength of 854 nm intersecting each other under an angle of 90 degrees. We can observe single lattice sites of the optical lattice with the new imaging technique. The current status of the experiment is presented.