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Collective atomic scattering and motional effects in a dense coherent medium
S L Bromley1, B Zhu1, M Bishof1
1JILA, NIST and Department of Physics, University of Colorado, 440 UCB, Boulder, Colorado 80309, USA.
Nature Communications
|March 18, 2016
Summary
We studied collective emission from ultracold strontium atoms. Coherently driven strong transitions show enhanced forward emission, while weak transitions reveal motion-dependent effects and frequency shifts.
Area of Science:
- Atomic physics
- Quantum optics
- Condensed matter physics
Background:
- Collective emission phenomena are crucial for understanding light-matter interactions in quantum systems.
- Ultracold atoms provide a highly controllable platform for investigating fundamental quantum phenomena.
Purpose of the Study:
- To investigate collective emission properties of coherently driven ultracold strontium-88 atoms.
- To explore the influence of atomic motion and transition strength on collective emission characteristics.
Main Methods:
- Performed experiments with ultracold strontium-88 atoms at 1 μK using strong and weak atomic transitions.
- Utilized two experimental setups sensitive and insensitive to atomic motion.
- Developed a theoretical model of coherent, interacting radiating dipoles to interpret measurements.
Main Results:
- Observed highly directional forward emission with >10^3 intensity enhancement for the strong transition.
- Noted substantial spectral line broadening for the strong transition.
- Found reduced forward enhancement and a density-dependent frequency shift for the weak transition due to atomic motion.
- Observed polarization dependences in fluorescence intensity and line broadening in the transverse direction.
Conclusions:
- Atomic motion significantly impacts collective emission, particularly for weak transitions.
- The strong transition is less susceptible to motion, leading to enhanced forward emission.
- Theoretical modeling accurately reproduces experimental observations of collective emission in ultracold atoms.
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