Bi-color atomic beam slower and magnetic field compensation for ultracold gases
Résumé
Transversely loaded bidimensional-magneto-optical-traps (2D-MOTs) have been recently developed as high flux sources for cold strontium atoms to realize a new generation of compact experimental setups. Here, we discuss on the implementation of a cross-polarized bi-color slower for a strontium atomic beam, improving the 2D-MOT loading and increasing the number of atoms up to ~ 10 9 atoms in the 461 nm MOT. Our slowing scheme addresses simultaneously two excited Zeeman substates of the 88Sr 1 S 0 → 1P1 transition at 461 nm. We also realized a three-axis active feedback control of the magnetic field down to the microgauss regime. Such a compensation is performed thanks to a network of eight magnetic field probes arranged in a cuboid configuration around the atomic cold sample and a pair of coils in a quasi-Helmholtz configuration along each of three Cartesian directions. Our active feedback is capable of efficiently suppressing most of the magnetically induced position fluctuations of the 689 nm intercombination-line MOT.