Berlin 2005 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 64: Quantengase IV

Q 64.7: Vortrag

Mittwoch, 9. März 2005, 12:30–12:45, HU Kinosaal

Observation of Single Atoms in Quantum Degenerate Gases — •Stephan Ritter, Anton Öttl, Michael Köhl, and Tilman Esslinger — Institut für Quantenelektronik, ETH Zürich, ETH Hönggerberg HPF D25, CH-8093 Zürich, Schweiz

We have observed single atoms from a quantum degenerate source. The detection process, based on a cavity QED method, is state-selective and non-destructive, which is a prerequisite for quantum gate operations.

We produce ultra-cold thermal and Bose-Einstein condensed ensembles of up to 2 million ⁸⁷Rb atoms in our novel experimental apparatus. Via radio frequency induced transitions between hyperfine states we are able to coherently output couple a continuous beam of atoms, which is directed through the non-destructive single-atom detector placed 40mm below the atomic cloud. The detector consists of a ultra-high finesse optical cavity with a finesse F=300.000 and a length of 180µm bringing us into the strong coupling regime. A single atom inside the cavity mode volume alters the resonance of the cavity significantly, thereby changing the transmission of a weak near-resonant probe beam. By recording the transmission of the probe light with a single photon counter we are able to detect single atom transits. The arrival times of individual atoms yield the statistics of the atomic source.

The next step of our experiment is to investigate and manipulate two-particle correlations. These are expected to differ fundamentally for degenerate and coherent thermal atomic beams.