Generating plasmonic vortex field with spin-dependent metananoslots

Abstract

In the last decade, the plasmonic vortex field has been studied extensively due to intriguing properties such as high field enhancement, optical singularity, and orbital angular momentum. In this work, we propose metananoslots that consist of paired orthogonal nanoslots arranged in an Archimedes spiral distribution. The metananoslots work as a plasmonic vortex lens that enables the synthesis of a highly tunable plasmonic vortex via the strong interaction between the illumination and the slots etched on the gold film. By adjusting the orientation of the orthogonal nanoslots pair, the metananoslots exhibit strong and controllable spin-dependent effects. The topological charge of the plasmonic vortex is found to be determined by both the incident spin and the geometrical topological charge of the metananoslots, making it suitable for applications such as optical manipulation, optical trapping, and optical data storage.