Research on the resolution of NR-PC flat lenses array detecting small target

On the basis of the Finite-Difference-Time-Domain (FDTD) method, the resolution of two dimensional triangular negative-refractive-photonic-crystal (NR-PC) flat lenses array is studied by scanning small target with dynamic scanning scheme. The NR-PC flat lens array studied in this paper is constituted by some identical flat lenses with different arrangements. Numerical simulation shows that the lateral scanning resolutions of NR-PC flat lenses array, as well as the detection area in lateral and longitudinal direction is significantly improved. Because the point defects are introduced in the propagation direction of light field (Z-axis direction) between two flat lens in lateral direction after the single flat lens combined as flat lenses array, leading to the optical field localized in the vicinity of point defects, and thus the lateral detecting and canning performance of NR-PC flat lenses array is improved. Then metal silver defects is introduced to replace some air holes in 3 × 2(three rows in Z-axis and 2 rows in X-axis) NR-PC flat lenses array. The later detecting and scanning resolution is further improved by an appropriate combination, nearly double of single non-defective flat lens. Theoretical basis of the detecting to small target by NR-PC flat lenses array is provided in this paper.