# Velocimetry of cold atoms by matterwave interferometry. (arXiv:1802.02190v1 [physics.atom-ph])

We present a method for the velocimetry of cold atoms by matterwave
interferometry, which we have used to measure the velocity distributions within
freely-expanding clouds of $^{85}$Rb atoms at temperatures of 17 and 33 $\mu$K.
Quadrature measurement using an asymmetric three-pulse technique allows
determination of the full analytic interferometer signal which yields the 1-D
velocity distribution with excellent fidelity. The technique is particularly
suited to ultracold samples, and avoids some of the artefacts of conventional
Doppler and time-of-flight methods.