Interferometric Detection of Pinned Interactions in Bismuth-Substituted Iron Garnet

The utilization of a bismuth-substituted iron garnet as a magnetooptic Faraday rotator (MOFR) has been reported for all-optical networking purposes as well as for other applications. Our measurements and observations demonstrate that the MOFR saturates once a significantly large magnetic field (\u3e225 G) is applied. After the applied magnetic field enters the saturation region, the material\u27s magnetic domains can become pinned at intermediate levels of magnetization. Pinning in this form has not been reported nor well studied for this application. In this paper, a method to detect and describe anomalous pinning in terms of Faraday rotation is presented. Measurements on the changes in the state of polarization that a pinned material produces are examined. This paper will also present practical methods for unpinning the MOFR material, which are traditionally considered to be challenging

Fiber based measurements of domain characteristics in bismuth substituted iron garnets

Bismuth substituted iron garnets (BIGs) are magneto-optic materials which exhibit Faraday rotation in an applied magnetic field. In the absence of an applied field, individual domains still exhibit Faraday rotation, though the bulk material does not. Using single mode fiber where the half power beam width is smaller in dimension than the magnetic domains of the material, individual magnetic domains of BIG samples are identified. A method for differentiating domains and determining domain alignment is presented. The Faraday rotation of individual domains is measured and reported.This is a manuscript of an article published as Kemmet, Sasha, Greg Bonett, Mani Mina, and Robert J. Weber. "Fiber based measurements of domain characteristics in bismuth substituted iron garnets." In 2008 IEEE International Conference on Electro/Information Technology, pp. 148-150. IEEE, 2008. DOI: 10.1109/EIT.2008.4554284. Copyright 2008 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Posted with permission