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Q: Fachverband Quantenoptik und Photonik
Q 46: Quanteneffekte: Lichtstreuung und Ausbreitung
Q 46.2: Talk
Thursday, March 5, 2009, 10:45–11:00, VMP 6 HS-E
Sub-wavelength position measurements with running wave driving fields — •Jörg Evers1 and Sajid Qamar1,2 — 1MPI für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg — 2Centre for Quantum Physics, COMSATS Institute of Information Technology, Islamabad, Pakistan
Spatial precision measurements are of interest both for a number of important applications and from a fundamental point of view. Applications arise, e.g., in life sciences, and more basic questions are related, e.g., to the uncertainty principle. A wide class of proposals for position measurements with sub-wavelength precision based on quantum optical ideas makes use of standing wave light fields. The standing wave acts as a ruler for the position measurement, and at the same time forms a spatial intensity pattern that can encode position information via a intensity-dependent dynamics of the atom.
Here, we discuss a setup for sub-wavelength position measumerents of quantum particles which in contrast to previous work operates with running-wave laser fields. The position is encoded in the phase of the applied fields rather than in the spatially modulated intensity of a standing wave. This is achieved by deliberately breaking the phase matching condition usually assumed in related setups. Due to the running fields, cases where the atom remains undetected since it is close to a node of the standing wave field are avoided. Reversing the directions of the driving laser fields allows to switch between different magnification levels.