Directional switching of surface plasmons in a parity-time-symmetric insulator-metal-insulator structure

In the present work, we study the generation and propagation of surface plasmon polaritons (SPPs) in a geometrically flat insulator-metal-insulator (IMI) structure with parity-time (PT) symmetric modulation on the dielectric layers. Unidirectional SPPs are generated by PT-symmetric modulation. Moreover, magnetic field switching is obtained between two metal-dielectric interfaces. It has been noticed that the metal thickness affects the oscillation frequency of excited SPPs along the direction of propagation. Also, we report that the field at the upper interface is manipulated by solely maneuvering the permittivity of the bottom dielectric. The magnetic field distribution of the present structure is studied using COMSOL Multiphysics software. To ensure the accuracy and reliability of the simulation results, comprehensive analytical investigations have also been conducted.