Electromagnetic Propagation in Homogeneous Media With Hermitian Permeability and Permittivity

Traditionally, the theory of light propagation in transparent, anisotropic media has assumed that the permeability of the medium was the same as that of the vacuum, or at least that it was isotropic. Conversely, the theory of microwave propagation in ferrites and garnets has assumed that the permittivity was isotropic in spite of the permeability being anisotropic and possibly, gyrotropic. (References 1 and 2 are examples of the optics tradition and the microwave tradition, respectively.) Both viewpoints are incomplete, particularly, when applied to in935 frared optics where anisotropy effects in both permeability and permittivity could be important. As a case in point, Yttrium Iron Garnet (YIG) is optically transparent at infrared wavelengths beyond 1 jum3 and at microwave frequencies; it could be used at wavelengths where the effects of permeability and permittivity are comparable. We develop the theory of electromagnetic wave propagation in a homogeneous medium where both the permeability and permittivity are anisotropic. Furthermore, by assuming that the permittivity and permeability tensors are Hermitian, not merely real and symmetric, we incorporate the more general effects of gyrotropy.