Dissociating the effect of different disturbances on the band gap of a two-dimensional photonic crystal

Abstract

In this article, we dissociate the effect of the three generic disturbances on the band gap of a bidimensional metallic photonic crystal made of parallel rods. The disturbances are investigated separately. They are deviations from the perfectly periodic position, the angle between rods constituting the photonic crystal and different sizes in rod diameters. Numerical simulations and experimental measurements have been performed in the microwave region and the results compared. The effects of these disturbances on a localized state are discussed as well. When the disturbance level is weak (i.e., a few percent), the band structure is conserved: the slopes at the edge and the band-gap width are the same as for the perfect structure. By contrast, the bandpass is reduced by about −1 dB. For an important disturbance the crystal becomes practically unusable due to the deep random modifications of its band structure. In all cases when the band gap exists, the transmission peak associated with the localized state is present.