Crossed-beam slowing to enhance narrow-line ytterbium magneto-optic traps

Abstract

We demonstrate a method to enhance the atom loading rate of a ytterbium (Yb) magneto-optic trap (MOT) operating on the 556 nm 1S0 → 3P1 intercombination transition (narrow linewidth Γg = 2π × 182 kHz). Following traditional Zeeman slowing of an atomic beam near the 399 nm 1S0 → 1P1 transition (broad linewidth Γp = 2π × 29 MHz), two laser beams in a crossed-beam geometry, frequency tuned near the same transition, provide additional slowing immediately prior to the MOT. Using this technique, we observe an improvement by a factor of 6 in the atom loading rate of a narrow-line Yb MOT. The relative simplicity and generality of this approach make it readily adoptable to other experiments involving narrow-line MOTs. We also present a numerical simulation of this two-stage slowing process, which shows good agreement with the observed dependence on experimental parameters, and use it to assess potential improvements to the method.

Enhancing the capture velocity of a Dy magneto-optical trap with two-stage slowing

“…This approach was introduced in a Yb experiment, where it gave a small enhancement to the MOT loading rate [14]. The Yb experiment has recently explored the approach in more detail [15]. In our experiment, angled slowing enhances the MOT population by more than a factor of 20.…”

Maximizing the capture velocity of molecular magneto-optical traps with Bayesian optimization

“…Since the remaining transverse velocity of the molecules will result in the expansion of the molecular cloud, a low longitudinal velocity at the end of the slower means a longer time of flight, and a larger molecular cloud reaching the trap center. Transverse cooling of the molecular beam ahead of the slowing process can have an effect on increasing the number of loaded molecules, but the improvement is limited [26], since the initial collimated beam will finally expand again due to the directional absorption and random re-emission of photons [27]. In contrast, an improvement to the capture velocity of the MOT will increase the MOT population by orders of magnitude [28], which is what we are seeking to do in this manuscript.…”

Design and simulation of a source of cold cadmium for atom interferometry

“…These beams are so-called crossed (or angled) slowing beams, a geometry which avoids interference with the 3D MOT itself and as has been demonstrated effectively in e.g. Dy, Er and Yb systems [50][51][52].…”