The Effect of Detuning on the Median Velocity of an Atomic Beam Slowed and Cooled by an Intense Optical Standing Wave

Abstract

Publisher Summary This chapter presents a study describing the effect of detuning on the most probable velocity of a beam of sodium atoms cooled in an intense standing wave laser field colinear with the atomic beam. Two distinct regimes were observed. For the highest intensities, the median velocity increased with increased detuning for detunings between 300 and 1500 MHz to the red of the 3 S 1/2 → 3P 3/2 transition. However, for more moderate intensities, the median velocity decreased as the detuning increased. These results were first compared to a qualitative model that focused on the crossover between stimulated heating of slow velocity atoms and spontaneous damping of fast atoms. The observations were then compared directly to the numerical calculation of the radiation forces and shown to be in good agreement. In conclusion, strong agreement is found between the experimental results and a numerical solution based on the theory. It was found that observed effects can be interpreted in terms of a crossover between stimulated and spontaneous processes that determine the force on an atom in an intense optical standing wave.