Berlin 2005 – scientific programme
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Q: Quantenoptik und Photonik
Q 3: Poster Quanteninformation, -kommunikation und Quantencomputer
Q 3.14: Poster
Friday, March 4, 2005, 11:00–12:30, Poster HU
GRIN-lens detector for observation of a single atom on a microchip — •Akifumi Takamizawa1, Tilo Steinmetz1, Rémi Delhuille1, Theodor W. Hänsch1, and Jakob Reichel1,2 — 1Max-Planck-Institut für Quantenoptik und Sektion Physik der Ludwig-Maximilians-Universität, München, Germany — 2Laboratoire Kastler Brossel de l’E.N.S, Paris, France
A single atom detector is necessary if single atoms are used for quantum information and computing. For the observation on a microchip, we are developing a fluorescence detector with a tiny gradient-index-lens (GRIN lens). The resonant fluorescence from a Rb atom with a wavelength of 780 nm is collected by the GRIN lens with a large NA of about 0.5 and coupled into a single mode fiber 4 mm behind the lens to take the fluorescence out of a vacuum chamber. In order to avoid the atom getting out of the detection region, optical dipole trapping will be performed at the focal spot of a laser beam with a wavelength of 830 nm introduced through the fiber. In preparatory measurements, we measured that the 830 nm-light is focused 8.6 µm farther from the lens than the 780 nm-light due to chromatic aberration. However, in spite of the aberration, the ratio of the fluorescence coupled into the fiber with respect to the total fluorescence is estimated to be 1.5 × 10−3, which value is sufficient for photon counting for the single atom detection. In this presentation, we will talk about the progress of the experiment of atom detection on a chip.