A quasi-electrostatic trap for neutral atoms

This thesis reports on the realization of a ''quasi-electrostatic trap'' (QUEST) for neutral atoms. Cesium ("1"3"3Cs) and Lithium ("7Li) atoms are stored, which represents for the first time a mixture of different species in an optical dipole trap. The trap is formed by the focused Gaussian beam of a 30 W cw CO_2-laser. For a beam waist of 108 #mu#m the resulting trap depth is #kappa#_B x 118 #mu#K for Cesium and #kappa#_B x 48 #mu#K for Lithium. We transfer up to 2 x 10"6 Cesium and 10"5 Lithium atoms from a magneto-optical trap into the QUEST. When simultaneously transferred, the atom number currently is reduced by roughly a factor of 10. Since photon scattering from the trapping light can be neglected, the QUEST represents an almost perfect conservative trapping potential. Atoms in the QUEST populate the electronic ground state sublevels. Arbitrary sublevels can be addressed via optical pumping. Due to the very low background gas pressure of 2 x 10"-"1"1 mbar storage times of several minutes are realized. Evaporative cooling of Cesium is observed. In addition, laser cooling is applied to the trapped Cesium sample, which reduces the temperature from 25 #mu#K to a value below 7 #mu#K. If prepared in the upper hyper-fine ground state sublevel, spin changing collisions are observed not only within one single species, but also between the two different species. The corresponding relaxation rates are quantitatively analyzed. (orig.)Available from TIB Hannover: RO 6920(22-2000) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman