Laser system for frequency domain velocimetry and atom interferometry experiments

We discuss the characterization and specifications of a home-built external cavity diode laser system that is suitable for frequency-domain cold-atom velocimetry and measurements of gravitational acceleration. The laser system is frequency stabilized using a modulation-free technique that lowers the temperature of a magneto-optical trap (MOT) in comparison with a MOT realized using a laser that relies on lock-in spectroscopy. The laser system also incorporates a feedback loop involving an acousto-optic modulator for intensity stabilization, which reduces the effect of low frequency vibrations. By integrating this laser with a home-built, dual-output radio frequency synthesizer, we are able to derive two laser beams with a precisely controlled relative detuning for frequency domain interferometry using laser-cooled atoms. The detuning can range from the mHz to the MHz level with a stability of 10 μHz.