Numerical investigation of the enhanced unidirectional surface plasmon polaritons generator

Abstract

A unidirectional surface plasmon polaritons (SPPs) generator with greatly enhanced generation efficiency is proposed. The SPPs generator consists of an asymmetric single nanoslit coated with a polyviny alcohol (PVA) film and a silver rectangle block. The generation efficiency of this SPPs generator is investigated using the finite difference time domain method. Due to the presence of the silver rectangle block, the SPPs generation efficiency of the asymmetric single nanoslit with PVA film can be greatly enhanced and the corresponding wavelength with the maximum enhancement factor can be tuned flexibly. The influence of the structural parameters on the generation efficiency is also investigated for the enhanced unidirectional SPPs generator.

Spin-controlled directional launching of surface plasmons at the subwavelength scale

“…Over the past few decades, many schemes have been proposed to achieve unidirectional SPP launching. [12][13][14][15][16][17][18] Furthermore, some schemes have also been proposed to actively tune the propagation direction of SPPs by additional external control, such as fishbonelike metasurface and slit by changing the handedness of the incident light (spins of photons), [19][20][21][22][23] graphene-loaded antenna pair by changing applied voltage. [24] In above schemes which tune the propagation direction of the SPPs by the optical spin, the structure unit does not have the ability of controlling the direction of propagation of photons by spin.…”