For a magneto-optical trap (MOT) formed near an atom chip using 87Rb atoms we have investigated various loading modes: loading from thermal atomic vapors and from a low-velocity atomic beam. The possibility of controlling MOT loading by spatial control of the atomic beam was demonstrated using an atomic beam,. This enables to increase the speed of loading atoms into MOT while maintaining an ultra-high vacuum in the area of the atomic chip. Under optimal loading conditions, the maximum number of atoms in MOT was 4.9 × 10⁷, whereas  the lifetime of atoms in MOT was 4.1 s.

Measured time dependence of the number of atoms in MOT near the atom chip. (a): Black curve (1) corresponds to the loading of atoms from thermal vapor; green curve (2) –loading from a low-velocity atomic beam whose position relative to the center of the atomic chip is shown on the panel (c); blue curve (3) - loading of atoms from a low-velocity atomic beam, whose  position is controlled using one-dimensional optical molasses (b). Figures (b) and (c) show photos of the illuminated atomic beam against the background of an atomic chip. The atomic beam propagates from left to the right and is illuminated by a narrow laser beam extending from top to bottom. The areas where of  the atomic beam intersects with the laser beam are shown in red. The microwire of the U-shaped trap (through which current flows to form the required magnetic field)  is highlighted in yellow.

P.I.Skakunenko et al.,
JETP Letters 119, issue 1 (2024)