Push beam spot-size dependence of atom transfer in a double magneto-optical trap setup

We have studied the dependence of atom transfer between two magneto-optical traps (MOTs) on the spot-size of a push laser beam in a double magneto-optical trap setup. It was observed that the spot-size of the push beam at vapor-chamber MOT (VC-MOT) affects significantly the transfer of atoms from the VC-MOT to an ultrahigh vacuum MOT (UHV-MOT). The number of atoms accumulated in the UHV-MOT first increases with the push beam spot-size and then decreases with it after attaining a maximum value, for a given power of the push beam. Our results show that the number of atoms accumulated in the UHV-MOT is dependent on the push beam spot-size, push beam power, and capture speed of the UHV-MOT.