Low-frequency-noise diode laser for atom interferometry

We investigate the influence of fast frequency fluctuations of an interrogation laser on the obtainable signal-to-noise ratio in Ramsey-Borde atom interferometers. It is shown that the excessive high-frequency noise of diode lasers can degrade the signal-to-noise ratio significantly in an atom interferometer. To overcome these limitations, we have devised a low-noise light source by frequency filtering a diode laser in a high-finesse cavity and further amplifying the transmitted power by injection locking a solitary laser diode. When this laser source was used for atom interferometry with laser-cooled calcium atoms, the signal-to-noise ratio could be improved further by a factor of 3.5 compared with the use of the unfiltered 1 Hz linewidth laser source. (C) 2008 Optical Society of America