Influence of surface termination morphologies on the imaging properties of a composite two-dimensional photonic crystal lens

摘要

By the numerical simulation based on the finite-difference time-domain method, we investigate the adjustability of image distance for the same object distance in two-dimensional photonic crystals (PCs). When we add a fraction of a metallic component to the center of each dielectric bar, the PC slab lens can form a non-near-field image and the image distance changes for different surface terminations formed by introducing cylinders at the surface layers whose geometric and physical parameters are different from those of the PC bulk. Furthermore, the image distance can be further tuned by combining the two kinds of cylinders at the surface layers with different ratios of slab length. These simulation results clearly show that the imaging properties can be controlled effectively by changing the surface termination of PC slab lenses.