Intensity Dependence for Trap Loss Rate in a Magneto-Optical Trap of Strontium

We have measured the collisional loss rate for cold strontium atoms held in a magneto-optical trap as a func-tion of light intensity in the regime of low intensity (2−6 mW/cm2). The results confirm our recently proposed model, where we showed that the sudden increase of loss rate at low intensities does not depend on hyperfine structure changing collision only. The model, which is based on radiative escape mechanism and a light inten-sity dependent escape velocity, is able to reproduce quite well the behavior of the experimental observations. The data here reported may be of importance for a recent proposed application for cold trapped 88Sr atoms, as well as other trappable alkaline earth metal atoms such as Ca.