Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 9: Cooling and Trapping II (joint session A and Q)
A 9.7: Vortrag
Dienstag, 3. April 2001, 19:00–19:15, H104
Super resolution of pulsed multi-photon Raman transitions — •Martin Weitz1,2, Francesco Cataliotti1, Rainer Scheunemann1,2, and Theodor W. Hänsch1,2 — 1Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching — 2Sektion Physik der Universität München, Schellingstr. 4, 80799 München
Multiple quantum transitions can occur in atomic systems strongly driven by ac fields. Using two pulsed optical fields and ultracold rubidium atoms confined in a CO2-laser dipole trap, we have examined higher order multiphoton Raman transitions. Multiphoton transfer with up to 50 photons is achieved between two stable Zeeman ground state sublevels driven by milliwatts of laser power. The multiphoton resonances are observed at subharmonic frequencies of the laser difference frequency required for two-photon Raman transfer.
We have investigated the spectral width of the multiphoton resonances for finite interaction times. It is observed that the spectral width of the multiphoton resonances can be far below the Fourier transform width of the driving optical pulses [1]. This line narrowing can be understood by considering that the multiphoton transfer involves the simultaneous interaction of several photons, such that the Heisenberg time-energy uncertainty relation involves the Fourier transform of a quantum state of several photons as a whole.
[1] F. S. Cataliotti, R. Scheunemann, T. W. Hänsch, and M. Weitz, submitted for publication.