Atom funnel running with evanescent light generated by a thick hollow light beam

The use of a hollow light beam reduces the loss of atoms inside and outside an evanescent-light funnel. Therefore, we superimpose an LG01 beam with a small hole onto a doughnut beam with a large outer diameter and couple the resultant hollow light beam to the 240-μm-wide outlet of an inverted trigonal-pyramidal funnel. Compared to the case where a Gaussian light beam is employed for generation of evanescent light, the flux intensity of the output cold 87Rb atoms rises 13-fold when the inner diameter of the 4.5-mm wide hollow light beam is 1.7 times as large as the size of the outlet under optimal blue-detuning conditions.