Date: Wed, 3 Dec 1997 09:39:31 -0500 (EST) From: Steve Gensemer To: Justin B Riggert > I am currently doing a project on the cooling and trapping of the 85 Rb > isotope. I was wondering if you could explain which state the electron > occupies when the F levels split (mf states) as the atom enters the > magnetic field. Will the electron always go into the top state? Look at this Webpage, it has a beautiful explanation of how a MOT works: http://dipmza.physik.uni-mainz.de/~www_exakt/neugart/motforce.htm Also I > was wondering about how strong your magnetic field is and the maximum > distance (nm) that the energy levels are shifted in this magnetic field. Our magnetic field _gradient_ (which is the important quantity in a MOT, as the magnetic field is 0 at the actual trap) is usually about 5-10 G/cm in the axial dimension. For your geometry, just figure out what current supply you have, where your field coils will be, and calculate how many turns of wire will produce the field you want. Most people just dial the current around until they maximize the number of atoms, and do their experiment. > Also I was wondering how far you can detune a laser and still have > significant absorbtion by the atom. With a cell MOT, which I assume you are using, the optimum detuning is usually 2 or 3 Gamma (linewidths.) More than 5 and you won't get very many atoms. You also should be aware of an article by Carl Wieman in the American Journal of Physics, on how to build a vapor cell MOT. It is very comprehensive.