Helicity Dependent Directional Surface Plasmon Polariton Excitation Using A Metasurface with Interfacial Phase Discontinuity

TL;DR

This paper introduces a metasurface design that enables controllable, helicity-dependent unidirectional excitation of surface plasmon polaritons, facilitating reconfigurable plasmonic circuits at optical frequencies.

Contribution

The work demonstrates a novel metasurface utilizing interfacial phase discontinuity for polarization-dependent, unidirectional SPP excitation at normal incidence, with experimental validation.

Findings

Achieved helicity-dependent unidirectional SPP excitation experimentally.

Enabled switching of SPP direction by changing incident light polarization.

Paves the way for electrically reconfigurable integrated plasmonic circuits.

Abstract

Surface plasmon polaritons (SPPs) have been widely exploited in various scientific communities, ranging from physics, chemistry to biology, due to the strong confinement of light to the metal surface. For many applications it is important that the free space photon can be coupled to SPPs in a controllable manner. In this Letter, we apply the concept of interfacial phase discontinuity for circularly polarizations on a metasurface to the design of a novel type of polarization dependent SPP unidirectional excitation at normal incidence. Selective unidirectional excitation of SPPs along opposite directions is experimentally demonstrated at optical frequencies by simply switching the helicity of the incident light. This approach, in conjunction with dynamic polarization modulation techniques, opens gateway towards integrated plasmonic circuits with electrically reconfigurable functionalities.