Doughnut mode magneto-optical trap

Abstract

We have developed a magneto-optical trap that is well suited for high-resolution spectroscopy. It uses a combination of doughnut mode (Laguerre–Gaussian TEM01) and TEM00 cooling beams rather than the usual TEM00 cooling beams. This configuration allows us to tailor the intensity distribution within the magneto-optical trap such that the atoms are cooled from the background vapor by the intense TEM01 beams and then trapped by the weak TEM00 beams. This greatly reduces the magnitude of the ac-Stark shift and the line broadening induced by the cooling lasers, allowing high-resolution spectroscopy to be performed in the presence of the cooling beams.