Optical-magnetostatic wave coupled-mode interactions in garnet heterostructures

Optical-magnetostatic wave coupling is considered theoretically in a five-layer structure consisting of three thin films, a cover, and a substrate. Two of the thin films are magnetic and are optimized separately for microwave and optical properties. The optical mode analysis permits the layers to be anisotropic provided the permittivity tensor is diagonal in the problem coordinate system. The magnetooptical properties are treated as a perturbation. Both Faraday and Cotton-Mouton effects are included. Coupled-mode theory is applied to the optical modes in this geometry for the general case of noncollinear propagation. The extra degrees of freedom provided by two magnetic films make it possible to adjust the microwave parameters so that the operating point is near the susceptibility resonance of the optical guiding layer, thereby enhancing the magnetic response of this layer