Coupling between Fano and Bragg bands in photonic band structure of two-dimensional metallic photonic structures

摘要

Frequency and transmission spectrum of two-dimensional array of metallic rodsis investigated numerically. Based on the recent analysis of the band structureof two-dimensional photonic crystal with dielectric rods [P. Marko\v{s}, Phys.Rev. A 92 043814 (2015)] we identify two types of bands in the frequencyspectrum: Bragg (P) bands resulting from a periodicity and Fano (F) bands whicharise from Fano resonances associated with each of the cylinders within theperiodic structure. It is shown that the existence of Fano band in a certainfrequency range is manifested by a Fano resonance in the transmittance. Inparticular, we re-examine the symmetry properties of the H- polarized bandstructure in the frequency range where the spectrum consists of the localizedmodes associated with the single scatterer resonances and we explore process offormation of Fano bands by identifying individual terms in the expansion of theLCAO states. We demonstrate how the interplay between the two scatteringmechanisms affects properties of the resulting band structure when the radiusof cylinders is increased. We show that a different character of both kinds ofbands is reflected in the spatial distribution of the magnetic field whichdisplays patterns corresponding to the corresponding irreducible symmetryrepresentations.