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Q: Fachverband Quantenoptik und Photonik

Q 32: Materiewellenoptik

Q 32.4: Vortrag

Mittwoch, 4. März 2009, 14:45–15:00, Audi-B

Atom Interferometry using Large Momentum Transfer Beam Splitters — •Sven Herrmann, Sheng-wey Chiow, Holger Müller, and Steven Chu — Physics Department, 382 Via Pueblo Mall, Varian 226, Stanford, CA 94305, USA

Light-pulse atom interferometers have been used for precision measurements e.g. of the fine-structure constant α, the local gravitational acceleration g, the Sagnac effect, or Newton’s gravitational constant. A way to increase the sensitivity of these measurements is to increase the splitting between the interferometer arms by using large-momentum transfer (LMT) beam splitters. Here, we present two realizations of such LMT beam splitters and their application in simultaneous conjugate Ramsey Borde interferometers in an atomic Cs-fountain, aiming to measure the photon recoil and thus the fine structure constant.
First, we have used multi-photon Bragg diffraction of atomic wave packets at an optical lattice as a beam splitter. Up to 30ℏ k can be transferred in a single diffraction. Second, we have embedded such beam splitters between de- and accelerating sections of Bloch oscillations. With both beam splitters we demonstrate interferometry with a splitting of up to 24ℏ k. Such beam splitters combined from Bragg diffraction and Bloch oscillations should ultimately allow to significantly increase the momentum splitting by increasing the number of Bloch oscillations. This opens the door to much improved precision measurements using atom interferometry.