Lin Sun

TL;DR: In this article, an approach with metasurfaces composed of nanoaperture arrays is proposed and experimentally demonstrated which can effectively manipulate the complex amplitude of SPPs in the near-field regime.

Abstract: With the recent development of the metasurface, generating an optical vortex in optical far or near fields is realized in various ways. However, to generate vortices in both the near and far fields simultaneously is still a challenge, although it has great potential in the future compact and versatile photonic system. Here, a bi-channel optical vortex generator in both the near and far fields is proposed and demonstrated within a single metasurface, where the surface plasmon vortex and the far-field optical vortex can be simultaneously generated under circularly polarized light. The ability of generating vortices with arbitrary topological charges is experimentally demonstrated, which agrees well with simulations. This approach provides great freedom to integrate different vortex generators in a single device and offers new opportunities for integrated optical communications, trapping, and other related fields.

TL;DR: The experiment results of scanning near-field optical microscopy for measuring the three-dimensional optical field distribution agree well both with designs and with numerical simulations, and this strongly supports the effectiveness and efficiency of the SWH method in the design of plasmonic devices that can fulfill manipulation and transformation of complicated-profile surface plasmons.

TL;DR: In this paper, the effect of the aspect ratio of a metal nanofinger surrounded by multiple concentric rings was investigated through both COMSOL multiphysics and finite-difference time-domain (FDTD) simulations.

TL;DR: In this article, a general imaging theory based on the reciprocity of electromagnetism and multipole expansion analysis was developed for near-field microscopy, which closely resembles the multipolar Hamiltonian for light-matter interaction energy, revealing the coupling mechanism of the probe-field interaction.