Deceleration of atoms with a fluctuating laser field

Abstract

In a recent publication1 we have analyzed the stability of the deceleration process of atoms in the Zeeman tuning technique2 by looking at the velocity profile of the atoms along the magnetic field. When the velocity [v(z)] follows the field profile [B(z)] we refer to this as adiabatic following of atoms because the absorption is adiabatically adjusted to each position so that v(z) follows B(z). This situation does not hold everywhere; in fact, at points where the absorption cannot be adiabatically adjusted the velocity ceases to follow the field interrupting the deceleration. The existence of fluctuations on the laser field produces dramatic changes on the expected behavior of the atoms during the deceleration. We have made numerical simulation and analytical investigation where v(z) is obtained for cases where the laser field has frequency and amplitude fluctuations produced by Markovian and Gaussian stochastic processes. In both cases, the deceleration is dependent on the spectral densities of the fluctuations. The process seems to be more sensitive to amplitude than to frequency fluctuation. These results are important in determining the desired characteristics of the laser source on atoms deceleration experiments.