TM band diagram of a waveguide in a honeycomb photonic lattice composed by triangular-shaped rods

Abstract

Using the plane wave expansion and the supercell technique, we calculate the TM band diagram of a waveguide in a honeycomb lattice that composed rods with triangular cross-sections embedded in air. For this study, we use GaAs rods with a dielectric function dependent on pressure and temperature. We report the existence of a defect band within the photonic band gap that presents large confinement for small wave vector values along the line defect. However, for large wave vector values, the defect band approaches the regular crystal bands, thus scattering a greater amount of energy. When the triangles are rotated, greater confinement and smaller scattering of energy is observed than that for unrotated triangles. Additionally, we report that the TM band diagram and the defect band may be tuned to higher frequencies by increasing the applied pressure.