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Q: Fachverband Quantenoptik und Photonik
Q 29: Poster I
Q 29.3: Poster
Dienstag, 3. März 2009, 16:30–19:00, VMP 8 Foyer
Control and detection system for a mobile high precision atom interferometer — •Sebastian Grede, Malte Schmidt, Alexander Senger, and Achim Peters — Humboldt Universität zu Berlin, AG Optische Metrologie, Hausvogteiplatz 5-7, 10117 Berlin
Matter wave interferometry has developed into a powerful tool for precise measurements of accelerations and rotations. Because of its capability to measure accelerations, it is also a suitable tool for high precision measurements of local gravity. We present subsystems of a gravimeter (developed within the projects FINAQS and the EuroQUASAR/IQS) based on atom interferometry and optimized for mechanical stability and mobility.
Our timing system controls the whole experimental setup, including the time critical Raman pulse sequence implementing the atom optical components of the interferometer. It is based on a PXI-Bus FPGA (Field Programmable Gate Array) card. Digital, analog and frequency output channels (provided via DDS) are all controlled by this FPGA card, resulting in low jitter between the different channels and a uniform user interface. We also present our approach for detecting the cold atoms, which is based on a differential absorption measurement using photo diodes. This cancels out the laser excess noise and mitigates the effect of the background vapour in the detection chamber. We thus aim for a quantum projection noise limited detection of atomic ensembles for atom numbers higher than 105. For smaller samples we would be limited by the fluctuations in the number of atoms from the background vapour in the detection beams.