An optical pumping primer

This pedagogical paper introduces the basic ideas of optical pumping. Some of the various optical pumping mechanisms are discussed, and illustrated by diagrams showing the experimental apparatus. The density matrix formalism is introduced and used to quantitatively examine the effects of optical pumping. Next some of the various spin relaxation mechanisms such as collisions and spin exchange between electrons and nuclei, are discussed. A good knowledge of elementary quantum mechanics is needed to follow the article.