Bulk and surface modes in a one-dimensional gyro-uniaxial photonic crystal

We examine the features of electromagnetic bulk and surface modes in a one-dimensional photonic crystal made up of lossless gyroelectric and uniaxial layers. We find a configuration that supports the propagation of a type of surface mode that can have either positive or negative group velocity, depending on the signs of the uniaxial permittivities. We also show how the introduction of gyrotropy qualitatively alters the photonic band structure, making it possible to modify the allowed frequency ranges within the structure just by varying the value of an external magnetic field. Exploiting an Otto configuration, we provide the analysis of a finite system where near-zero reflectivity values correspond to large Goos-H"anchen shifts. We also explore low-symmetry configurations where waves exhibit nonreciprocal behaviors.