Subwavelength focusing of a cylindrically symmetric plano-concave lens based on a one-dimensional Thue-Morse photonic quasicrystal

摘要

A cylindricatly symmetric plano-concave lens based on a one-dimensional (1D) Thue-Morse photonic quasicrystal (PQC) is proposed. Sub-wavelength focusing characteristics with an incident cylindrical vector beam are investigated. Numerical results reveal that the lens can exhibit polarization-independent, high-resolution, and low-side-lobe characteristics, simultaneously for near-field and non-near-field. Furthermore, the lens can achieve perfect focusing and size-independent characteristics with equal-proportion scaling of the size of the lens at the corresponding center frequency. The focusing mechanisms of the lens are explained by analyzing the transmission spectrum, dispersion relation of a 1D periodic photonic crystal, and transmission spectrum of the 1D Thue-Morse PQC. (C) 2018 The Japan Society of Applied Physics.