Magnetooptic properties and applications of bismuth substituted iron garnets

Abstract

Using the results of the phenomenological and microscopic description of magnetooptically active transitions presented in the beginning of the article, a review is made of the progress achieved in the understanding of the origin of the large bismuth induced magnetooptic effects in iron garnets. For applications involving the Faraday configuration, optical efficiencies are determined by the ratio of Faraday rotation (θ) to optical absorption (α). The dependence of θ/α on such variables as bismuth concentration, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4\piM_{s}</tex> and impurity ions is discussed with its spectral behavior. Finally, the behavior of bismuth substituted iron garnets in devices previously devised using unsubstituted iron garnets is discussed, in conjunction with devices which have only become feasible as a consequence of improvements in the optical properties of such iron garnets.