Oxford University Press eBooks

Coherent Interactions of Fields and Atoms

Stephen Colby Rand

Published May 26, 2010• 0 citations

Abstract

Chapter 5 begins the systematic application of the density matrix to describe optical interactions. First, stationary two‐ and three‐level atoms interacting with a traveling wave are compared to show that the presence of additional levels changes the saturation behavior of atoms. Then motion of the atoms is introduced and the phenomena of spatial and frequency‐domain hole‐burning are analyzed. Special effects due to standing waves, such as the light shift are covered in this section. Next, tri‐level coherence is considered, to extend the concept of coherences to two‐photon transitions or Zeeman interactions in folded Λ‐ or V‐systems. Higher (third‐)order interactions are also analyzed. This includes four‐wave mixing and pump‐probe spectroscopy which form the basis of common nonlinear laser spectrocopies. The chapter closes by pointing out that higher order coherent interactions, which can sometimes be important if they are deliberately phase‐matched, are best treated using a diagrammatic calculational technique based on Feynman diagrams.

DOI: 10.1093/acprof:oso/9780199574872.003.0005

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