Hannover 2010 – scientific programme

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A: Fachverband Atomphysik

A 3: Ultra-Cold Atoms: Trapping and Cooling (with Q)

A 3.4: Talk

Monday, March 8, 2010, 14:45–15:00, A 320

A miniaturized microwave guide for electrons — •Johannes Hoffrogge and Peter Hommelhoff — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching bei München

We are currently setting up an experiment aiming at guiding electrons in an AC quadrupole guide. The use of miniaturized trapping structures allows for an exceptional tight confinement in the transverse direction. In combination with a single atom tip as electron source, electron injection near the transverse ground state of motion may become feasible. This would lead to a well-defined motional quantum system with potential applications in, e.g. electron interferometry. While ion traps are driven at radiofrequencies, the stable confinement of electrons demands operation at microwave frequencies because of their much higher charge to mass ratio. This can be accomplished by the combination of the electrode layout of a microfabricated planar Paul trap with that of a microwave transmission line on a planar substrate. In stark contrast to the case of ion traps, for a guide with a length comparable to the wavelength of the driving field, the microwave guiding properties of the trap structure become important. Here, we show results of a detailed microwave analysis of a planar five wire structure driven at 1 GHz. As another important element of the experiment, an optimized incoupling structure for a smooth transition from the field free region to the trapping field will be dicussed. We also present experimental results of a first realization with trap frequencies around 100 MHz and radial trap dimensions of several hundred micrometers.