Study Of Devices And Waveguide Characteristics Based On Surface Plasmon Polariton And Phonon Polariton

As a new science,micro/nano-photonics provides the new way for the developments of integrated and miniaturized optical devices and associated systems in the future.As an important branch of its research area,surface plasmon polariton has crucial application value in micro/nano-optical device,energy utilization and bio-sensing.Graphene is a two-dimension material with good electric property and optical property.The surface plasmon polariton supported in graphene owns wonderful tunability,strong field confinement and low propagation loss.As a natural material with hyperbolic dispersion property,hexagon boron nitride can support phonon polariton which exhibits characteristic of lower propagation loss than graphene.The main research contents of this thesis are utilizing materials like graphene and hexagon boron nitride,combined with metal grating or silicon grating,to propose some kinds of tunable optical devices and refractive index sensors.This thesis also shows the researches of the propagation characteristics and field confinements for the hybrid structures above.The main research achievements of this thesis are as follows:(1)A mid-infrared tunable absorber based on silver grating-graphene-spacer-silver hybrid structure is proposed.By tuning the geometries of the silver-air grating and Fermi energy level of graphene,the absorption at the peak can exceed 99.9%.By replacing the air in the silver grating to refractive index sensing media,a mid-infrared refractive index sensor with sensitivity of 2.3 ?m per refractive index unit is proposed and demonstrated.(2)A mid-infrared tunable narrow-band plasmonically induced transparency based on graphene-spacer-silicon grating hybrid structure and its corresponding slow light effect are proposed.The quality factor of the plasmonically induced transparency peak can exceed 108 and the group delay of the plasmonically induced transparency window is over 0.44 ps via manipulating the related parameters of graphene,spacer and silicon grating.A slow light device based on graphene-silicon grating with graded periods is further proposed.Its bandwidth of trapping light can be?0.7?m.(3)A plasmonically induced transparency system based on hexagon boron nitride-graphene-silica grating structure is presented.Plasmonically induced transparency effects both within the upper reststrahlen(RS)band and outside the RS band can be realized via changing the geometry parameters of the structure and the chemical potential of graphene.The group delay of the plasmonically induced transparency window within the upper RS band is over 0.15 ps.A refractive index sensor based on the basic structure above is further proposed.Its sensitivity outside the RS band is 0.336 ?m per refractive index unit.(4)A graphene-coated hexagon boron nitride nanowire pair waveguide structure is proposed.This structure can support hybrid plasmon-phonon-polariton modes and phonon-polariton modes.The research results show that the lowest order mode of hybrid plasmon-phonon-polariton modes exhibits stronger field confinement ability and lower propagation loss property than the similar type hybrid modes.By tuning the substrate radius or Fermi level of graphene,the field enhancement of the lowest order mode of the hybrid plasmon-phonon-polariton modes can reach over 105.(5)The waveguide structure based on hexagon boron nitride sandwiched by two graphene nanowire is studied.The relationship between the electric components and magnetic components for the transverse magnetic(TM)modes in the hexagon boron nitride region with anisotropic dielectric constant is derived from the Maxwell's equations.By combining the boundary conditions,the characteristic equation for the TM modes supported in the proposed multilayer waveguide structure is further presented.(6)For the structure based on hexagon boron nitride sandwiched by two graphene nanowire waveguide,the dependences of the real part of the effective mode index and figure of merit of the hybrid phonon-acoustic plasmon-polariton modes and hybrid phonon-optical plasmon-polariton modes on the chemical potential of graphene and geometry parameters are studied and demonstrated,respectively.The influences of the plasmon-phonon coupling on the dispersion characteristics of these two types of hybrid modes are analysed.By tuning the chemical potential of graphene,the figure of merit of the hybrid phonon-acoustic plasmon-polariton modes can reach over 180.