3D Monte-Carlo Simulation of Zeeman Slower System with Two Level Atoms

Abstract

We report three dimensional numerical simulations of a Zeeman slower system with two level atoms. We choose the magnetic field intensity distribution from experimental data and atomic conditions from population analysis of the transitions between F=2 and F=3 lines of the Na atom. We use the Monte-Carlo method for simulation. We generate three kinds of random numbers to specify the initial velocity of the atoms and one more random number for the event of the spontaneous emission. We treat the stimulated emission with numerical solution of the Bloch equation for two level atoms. We put atoms into the Zeeman slower system one by one and follow the motion of each atom. Two forces are considered; one is the intensity gradient force caused by stimulated emission and the other is the divergence force caused by spontaneous emission. We employ a parameter related with the atomic states at the exit port of the Zeeman slower. This parameter is related with space distribution and the velocity distribution of the atom at the exit. We analyze threekinds of the laser beam conditions; one is the focusing condition, another being intensity conditions and the last one being intensity shape conditions of the laser beam front.