Realization of an intense cold Rb atomic beam based on a two-dimensional magneto-optical trap: Experiments and comparison with simulations

Abstract

We discuss the implementation and characterization of the source of a slow, intense, and collimated beam of rubidium atoms. The cold atomic beam is produced by two-dimensional magneto-optical trapping in directions transverse to the atomic beam axis and unbalanced Doppler cooling in the axial direction. The vacuum design allows use of relatively low laser power and a considerably simplified assembly. The atomic beam has a high flux of about $2\ifmmode\times\else\texttimes\fi{}{10}^{10}\phantom{\rule{0.3em}{0ex}}\mathrm{atoms}∕\mathrm{s}$ at a total cooling laser power of $55\phantom{\rule{0.3em}{0ex}}\mathrm{mW}$. It has a narrow longitudinal velocity distribution with mean velocity $15\phantom{\rule{0.3em}{0ex}}\mathrm{m}∕\mathrm{s}$ with full width at half maximum $3.5\phantom{\rule{0.3em}{0ex}}\mathrm{m}∕\mathrm{s}$ and has a low divergence of $26\phantom{\rule{0.3em}{0ex}}\mathrm{mrad}$. The high flux enables ultrafast loading of about ${10}^{10}$ atoms into a three-dimensional (3D) magneto-optical trap within 500 ms. The variation of the atomic beam flux was studied as a function of the rubidium vapor pressure, cooling laser power, transverse cooling laser beam length, detuning of the cooling laser, and relative intensities of the cooling beams along the atomic beam axis. We also discuss a detailed comparison of our measurements of the cold atomic beam with a 3D numerical simulation.