Magneto-optic trapping of lithium using semiconductor lasers

We present an experimental investigation of a magneto-optical trap for Li-7 atoms which is operated exclusively with low-power single-mode diode laser s. A master-slave scheme based on injection locking of two diode lasers is employed to reach sufficiently high power of tunable narrowband radiation. The trap is loaded from an atomic beam which is decelerated in a compact Ze eman-slower with decreasing field resulting in trap loading rates close to 10(8) atoms/s. The dependence of loading rate, trap spring constant, temper ature, number and density of trapped atoms on the laser parameters is studi ed. More than 10(9) atoms are accumulated at a density approaching 10(11) a toms/cm(3). Since the highest particle numbers are achieved at trap laser d etunings of several linewidths from resonance, light-assisted inelastic col lisions are of minor importance, and the number of trapped atoms is mainly limited by background gas collisions. The volume occupied by the trapped at oms is found to be independent of the particle number for densities up to 1 0(10) atoms/cm(3) and particle numbers up to 10(8). The lowest measured tem perature 300 +/- 50 mu K corresponds to a momentum spread of 7 photon recoi l momenta. (C) 1998 Elsevier Science B.V. All rights reserved.