Surface-plasmon-like distributions in metallic square shield array

In this work, we present the numerical study of 2D photonic crystals (PCs) made of square metallic shields distributed in a square arrangement embedded in air for the transversal electric (TE) polarization in the Γ - X direction. It is presented the modification of the photonic band structure (PBS), which shows the redistribution of bands with low dispersion at lower and higher frequencies around the surface plasmon frequency (SPF) with the decrease in the width of the shield walls. Considering the distributions of |Hz|2 and |E|2 in the unit cell, it is observed high intensity values in the metallic region, even for low frequencies, with a distribution like surfaces plasmons, due to the interaction of the electromagnetic modes located at the inner and the exterior surfaces of the shield. Also, it is observed that the electric field is strongly localized in the inner hole of the shield at low frequencies, which is quite different from the conventional rod geometry. These results would be utilized in electric field confinement for technological applications.