Gyrotropic Bandgaps, Degeneracy Lifting and Selective Suppression of Bloch States in Photonic Systems

TL;DR

This paper investigates how birefringent magnetophotonic crystals can break degeneracy and suppress certain Bloch states, leading to gyrotropic bandgaps and polarization reorientation in photonic systems.

Contribution

It introduces the phenomenon of degeneracy breaking and mode suppression in birefringent magnetophotonic crystals, revealing new ways to control light propagation.

Findings

Degeneracy breaking occurs in asymmetric contradirectional coupling.

Gyrotropic bandgaps partially overlap inside the Brillouin zone.

Significant magneto-optic polarization reorientation at bandgap edges.

Abstract

Birefringent magnetophotonic crystals are found to exhibit degeneracy breaking for asymmetric contradirectional coupling in planar waveguides. Fundamental to high-order local normal mode coupling leads to partially overlapping gyrotropic bandgaps inside the Brillouin zone and partial suppression of Bloch mode propagation. A large magneto-optically active reorientation in polarization state is found for allowed Bloch modes at bandgap edges.