Study On The Properties Of Unidirectional Reflectionlessness In Plasmonic Waveguide System

Surface plasmon polariton is a kind of electron rarefaction wave that propagates along the interface between metal and dielectric.This electron rarefaction wave is generated by the coupling of light and free electrons on the metal surface.It has the advantages of photonics speed,electronic scale,and breaking the limit of diffraction and sub-wavelength limitation.It can manipulate light in the sub-wavelength range and is currently the most promising information processing carrier for nano-optical integrated devices.With the continuous development of nanotechnology,surface plasmons have been applied in many fields such as biology,medicine,optical storage,and optical integrated devices.This thesis mainly studies the high dispersion and controllable unidirectional reflectionlessness phenomenon in the surface plasmonic waveguide system.The research contents are as follows:Firstly,the dual-band unidirectional reflectionlessness and perfect absorption phenomenon are studied in two high-order mode resonators which are end-coupled to plasmonic waveguide system.Based on numerical simulation and analytical calculation,we find that compared with eigen-mode resonators,higher-order mode resonators have obtained higher quality factors,which are 257.6 and 217.2,respectively.Secondly,using the two square electro-optical materials resonators near-field coupled to plasmonic waveguide system,the controllable single-band unidirectional reflectionlessness and perfect absorption are studied.We propose a method to control the refractive index of the electro-optical material through different external voltage on a special design.When the external voltage changes,this special design can change resonant frequency of one resonator,while resonant frequency of another resonator unchange.Finally,the dual-band unidirectional reflectionlessness is studied in two electrooptical materials annular resonator end-coupled to plasmonic waveguide system.By observing the z-component magnetic field distribution in unidirectional reflectionlessness point,we find that the eigen-mode and the higher-order mode plasmon resonance appear at two different voltages.