Magnetooptic bubble-domain devices

The practical feasibility of display and sensing systems using the magnetooptic properties of the three most widely discussed bubble-domain materials is discussed; the orthoferrites (100 μm bubbles), the garnets (10 μm bubbles), and the hexaferrites (1 μm bubbles). It is found that on a per bubble basis, the incident light intensity at the surface of the magnetic platelet necessary for both applications is remarkably close for all three materials, varying only between several microwatts and several tens of microwatts. Because of the large range of bubble diameters, however, the power per unit area varies from a quite tolerable 0.025 W/cm2in orthoferrites to a prohibitive 114 W/cm2for hexaferrite. Thus orthoferrite magnetooptic devices should be relatively straightforward, garnet devices will require careful heat sinking, and hexaferrite devices seem very doubtful.