We have studied a general technique for laser cooling a cloud of polarized trapped atoms down to the Doppler temperature. A one-dimensional optical molasses created with polarized light cools the axial motional degree of freedom of the atoms in the trap. Cooling of the radial degrees of freedom can be modeled by reabsorption of scattered photons in the optically dense cloud. We present experimental results for a cloud of chromium atoms in a magnetic trap. A simple model based on rate equations shows quantitative agreement with the experimental results. This scheme allows us to readily prepare a dense cloud of atoms in a magnetic trap with good starting conditions for evaporative cooling.
© 2003 Optical Society of America
Piet O. Schmidt, Sven Hensler, Jörg Werner, Thomas Binhammer, Axel Görlitz, and Tilman Pfau, "Doppler cooling of an optically dense cloud of magnetically trapped atoms," J. Opt. Soc. Am. B 20, 960-967 (2003)