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 6.835GHz ±25MHz for hyperfine
transitions in 87Rb. The presented microwave source combines two
commercially available frequency synthesizers: an ultra-low-noise oscillator at
7GHz and a direct digital synthesizer for radiofrequencies. We demonstrate
a low integrated phase noise of 580μrad in the range of 10Hz to
100kHz 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.Comment: The following article has been submitted to Review of Scientific
Instruments. After it is published, it will be found at
https://aip.scitation.org/journal/rsi. v2: Typo in the abstract correcte