Interaction of a strongly focused light beam with single atoms

Abstract

In this thesis, we investigate the interaction of a strongly focused Gaussian light beam with a single Rubidium-87 atom, trapped in a far off-resonant 980nm optical dipole trap. Two classes of experiments were performed, one with a weak coherent continuous wave light and another with strong coherent light pulses. For the first case, the experimental quantities of extinction (8.2%), reflection(0.16%) and induced phase shift(1°)were measured and related back to the quantity known as the Scattering Ratio.

In the pulsed experiments, we investigated the effect of shaping the pulse temporally. The rising exponential and rectangular pulse shapes with different average photon number and different length were compared. For bandwidths of the pulses close to the spontaneous atomic transition linewidth, a rising exponential pulse typically performs better.