Laser collimation of a Li atomic beam has been studied to create an intense collimated atomic beam. The gain of Li atomic intensity in the beam has been measured as functions of laser collimation parameters, such as laser-atom interaction length, laser-frequency detuning and laser power density. The Li intensity gain depends non-linearly on the laser-atom interaction length due to the longitudinal velocity distribution of the thermal Li beam (550°C). In the high laser power regime, the dependence of the Li intensity gain on the laser power and detuning disagrees with the theoretical prediction of the scattering force. These findings are explained by considering the saturation broadening of the Li absorption line. By optimizing the laser collimation parameters, 3.2-fold increase of the atomic intensity is attained for the collimated Li beam with the transverse velocity spread of±5m/s.
