Tunable optical filters and multichannel switches based on MIM plasmonic nanodisk resonators inset a silver bar

Abstract

A tunable band-stop filter and an unusual multichannel optical switch based on metal-insulator-metal (MIM) plasmonic nanodisk resonators with an inset silver bar are proposed and investigated numerically by using the finite-difference time-domain (FDTD) method. Simulation results reveal that the transmission spectrum of the filter can be tuned and modified efficiently not only by varying the width and length of the silver bar but also by rotating the silver bar. The refractive index of the dielectric surrounding the silver bar is changed for realizing the tunability of a broad stopband. Rotating the silver bar makes the surface plasmon polaritons (SPPs) pass different outputs of the multichannel optical switch. In all calculations, the outer size of the nanodisk is unchanged. The proposed structures will undoubtedly be useful for optical filtering and switching in ultra-compact plasmonic devices.