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Q: Fachverband Quantenoptik und Photonik
Q 6: Quantum Effects: Light Scattering and Propagation
Q 6.2: Talk
Monday, March 14, 2011, 11:00–11:15, SCH A01
Highly resonant spin noise spectroscopy at the D2 rubidium transition — •Hauke Horn1, Ernst Rasel2, Luis Santos3, Michael Oestreich1, and Jens Hübner1 — 1Institute for Solid State Physics, Leibniz University Hannover, Appelstr. 2, 30167 Hannover, Germany — 2Institut für Quantenoptik, Leibniz University Hannover, Welfengarten 1, 30167 Hannover, Germany — 3Institute for Theoretical Physics, Leibniz University Hannover, Appelstr. 2, 30167 Hannover, Germany
We measure the fluctuating magnetization noise of an ensemble of non-interacting rubidium atoms with high sensitivity Faraday rotation spectroscopy. This measurement technique called spin noise spectroscopy allows us to probe the equilibrium spin dynamics of our sample. In spin noise spectroscopy, a magnetic field is applied in Voigt geometry to modulate the occurring spin noise with the Larmor frequency ωL=gI µB B /ℏ with atom g–factor gI, Bohr magneton µB and magnetic field B. Usually, the laser is widely detuned from optical resonances to avoid unwanted excitation effects (as e.g. carrier heating in semiconductors).
Here, we probe the Faraday rotation noise under resonant and non-resonant conditions in terms of non-linear magneto–optics. We tune the laser ± 10 GHz around the Rb D2-transition and see a clear signature of coherent couplings of the participating electronic levels and explain it fully by extended Bloch equations including all D2 hyperfine states as well as homogeneous and inhomogeneous processes like pressure broadening of the resonances and diffusion of the atoms.