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Updated: Jul 23, 2025

Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Dynamical low-noise microwave source for cold-atom experiments
Bernd Meyer-Hoppe1, Maximilian Baron1, Christophe Cassens1
1Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, D-30167 Hannover, Germany.
Abstract:
The generation and manipulation of ultracold atomic ensembles in the quantum regime require the application of dynamically controllable microwave fields with ultra-low noise performance. Here, we present a low-phase-noise microwave source with two independently controllable output paths. Both paths generate frequencies in the range of 6.835 GHz ± 25 MHz for hyperfine transitions in 87Rb. The presented microwave source combines two commercially available frequency synthesizers: an ultra-low-noise oscillator at 7 GHz and a direct digital synthesizer for radio frequencies. We demonstrate a low integrated phase noise of 480 µrad in the range of 10 Hz to 100 kHz and fast updates of frequency, amplitude, and phase in sub-µs time scales. The highly dynamic control enables the generation of shaped pulse forms and the deployment of composite pulses to suppress the influence of various noise sources.
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