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.