Focusing on the graded negative index flat by annular photonic crystal

摘要

Focusing on the graded negative index lens made by annular photonic crystals (APCs) are theoretically studied. The graded annular photonic crystal (GAPC) is composed of a dielectric-rod and a circular-air-hole array in a triangular lattice. The grade index is achieved by gradual modification of the radius of the rod along the transverse direction to propagation. The properties of the GAPC are analyzed by using the Plane Wave Expansion (PWE) method and numerical simulation is studied by using the Finite-Difference Time-Domain (FDTD) method. The results show that the GAPC can realize the focus of plane waves and the focal length can be designed with the wave frequency.