关键词: 表面等离激元, 表面等离激元透镜, 有限时域差分, 局域场增强

Abstract: A plasmonic lens based on a thin conical dielectric film adhered to a metallic disk is proposed. The structure converges normal incident light into a circular focal stripe. The circular focal stripe decreases in size with the decreasing of the thickness of the dielectric film, and converges into a focal spot when the thickness is smaller than a critical value. Moreover, the enhancement of the local field can also be improved by using the structure.

Key words: surface plasmon polarition (SPP), plasmonic lens (PL), finite-difference time-domain (FDTD), local field enhancement (LFE)