Design Of Plasmonic Waveguide And Metasurface

Surface plasmon polariton(SPP)is a kind of surface electromagnetic wave propagating along the interface between metal and dielectric.SPP can enhance localized field and break the diffraction limit,possessing the ability to manipulate light in subwavelength scale.Therefore,SPP plays an important role in the design of nanophotonic devices.Compared with traditional photonic waveguide,plasmonic waveguide have a smaller footprint and can be used on high-compact optical circuits.Metasurface can manipulate light via surface plasmon resonance on the nanostructure,achieving novel functions.Nowadays,the two topics are both hotspots in Nanophotonics.In this paper,we propose a series of nanophotonic devices based on theoretical analysis and Finite-Difference Time-Domain simulation(FDTD): we have designed several different on-chip optical devices based on plasmonic metal-insulator-metal(MIM)waveguide system;we also have investigated a graphene-metal metasurface in terahertz regime with dynamic control.The main works include:On-chip plasmonic filter and demultiplexer based on square ring resonator.The ring resonator is introduced in MIM demultiplexer for the first time.On-chip plasmonic sensor with ultra-high figure of merit(FOM)based on concentric ring resonator.This sensor has a considerable sensitivity,meanwhile possessing an ultra-high FOM.On-chip optical switching based on plasmon-induced transparency(PIT).We utilize nonlinear material to achieve tunable PIT,then realize three different schemes of optical switching.On-chip slow light enhancement with gain material.We introduce gain material to enhance the delay time of slow light based on PIT.On-chip directly coupled structure for reducing the manufacture difficulty.We realize a special directly coupled structure to achieve PIT,of which the fabrication is easier.Active control of broadband PIT based on graphene-metal hybrid metasurface.By applying voltage,both the strength and bandwidth of PIT can be switched.