Narrow-line cooling of 87Rb using 5S 6P open transition at 420 nm

Abstract

A magneto-optical trap (MOT) at narrow transition offers lower temperature and hence is the key for producing a high phase density atomic cloud and subsequently quantum degeneracy with a large number of atoms for many elements. In this paper, we describe the loading of 87Rb atoms in the MOT using a narrow open transition (5S 6P) at 420 nm (i.e. blue MOT) from the routinely implemented MOT using a broad cyclic transition (5S 5P) at 780 nm (i.e. IR MOT). Using the four times narrower transition, we have trapped around 108 atoms in the MOT with a typical temperature of around K. We have also studied the behavior of the blue MOT with various parameters such as hold time, detuning, and power of trapping and repumper beams.