Focusing, Imaging and Fourier Transforming With a Large Numerical Aperture, Dielectric Flat Photonic Crystal Lens in Metamaterial Regime

Abstract

An untraditional Gradient Index Photonic Crystal (GRIN PC) is employed within the long wavelength regime to exhibit focusing, imaging and Fourier Transforming. A very large numerical aperture is aimed by breaking the paraxial wave approximation and the slowly changing refractive index assumption. This untraditional GRIN PC is shown to exhibit very similar lensing characteristics as its analytically solvable counterparts demonstrate. The results suggest that Fourier Transforming together with Fractional Fourier Transforms can be obtained from the present design. The performance of the GRIN PC lens is very much dependent on the excitation source as it is expected from GRIN optics and adiffractional propagating beams over large distances can be obtained.