Optical collimation of an atomic beam using a white light molasses

We investigate optical collimation of an atomic beam using a spectrally broadened white light molasses. We compare this technique with the standard technique using an atomic collimator and find that, under certain conditions, the white light molasses is preferable. Specifically, a white light molasses is suitable for atomic beams with relatively low mean velocities and broad velocity distributions, for example, a beam effusing from a cryogenically cooled reservoir. This result is demonstrated by numerically modeling the atomic trajectories of argon atoms effusing from a cryogenically cooled reservoir. We find that, given sufficient power, a white light molasses captures a larger fraction of atoms when compared to an atomic collimator, and the velocity distribution of the resulting beam is shifted toward slower velocities. Further, an optical molasses is geometrically relatively simple compared to an atomic collimator; therefore, the complexity of the in-vacuum optical arrangement can be significantly reduced. (C) 2015 Optical Society of America