Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 48: Ultra-cold atoms, ions and BEC III (with A)
Q 48.3: Vortrag
Donnerstag, 3. März 2016, 11:30–11:45, f107
Local Ionization of Ultracold Gases by Femtosecond Laser Pulses — •Bernhard Ruff1,3, Philipp Wessels1,2, Juliette Simonet1,2, Klaus Sengstock1,2, and Markus Drescher1,3 — 1The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany — 2Zentrum für Optische Quantentechnologien, Hamburg, Germany — 3Institut für Experimentalphysik, Hamburg, Germany
The combination of ultracold atomic systems and ultrafast laser pulses promises insight into the coherence properties of macroscopic dissipative quantum systems and enables the preparation of hybrid quantum systems through local ionization of atoms in strong laser fields.
We report on the investigation of ultracold 87Rb gas exposed to femtosecond laser pulses at 515 nm wavelength and 290 fs pulse duration. The light pulses ionize atoms of the atomic cloud within the focus region (7 µm waist) of the beam via two-photon absorption. The number of ions generated can be controlled by tuning the intensity or the wavelength of the laser pulses. The remaining atoms are detected by resonant absorption imaging either in situ or after time of flight.
Atomic losses evident as a hole in the trapped cloud are evaluated and show a non-linear increase with respect to the pulse energy corroborating the generation of ions in a multiphoton process. Additionally results on the relaxation dynamics of thermal clouds and condensates after exposure to a single pulse will be discussed as well as further perspectives on the detection of charged fragments.