Application Of Surface Plasmon Polariton In Optical Tunable Filter

The optical communication is one of the most important pillars in the information field,which has recently been developing at a high speed.With the continuous improvement of nanomaterial processing technology,scientific researchers combine communication devices with nanostructures and further study its application based on surface plasmon polaritons,in order to solve the problems that restrict the optical communication's development such as high thermal resistance,large size and low integration.The optical communication devices based on surface plasmon polaritons have superior characteristics.,which can effectively reduce engry loss,improve integration and build optical devices on sub-wavelength level.Surface plasmon polaritons can transmit electromagnetic wave on nanometer scale,and break through the diffraction limit with the ability of enhance transmission.Therefore,it will occupy an important position in the future development of optical communication devices.Metal-insulator-metal(MIM)waveguide is beneficial to excite the surface plasmon polariton,whose structure is simple,and easy to process.Many researchers have proposed different optical communication devices based on MIM waveguide structure,such as Mach-Zehnder inter-ferometers,optical switch,and optical sensor.Thus,it's very important to understand the production principles and physical properties of surface plasmon polaritons in MIM waveguide.The main work is completed as following:First of all,this paper studied the Drude model of metals,and discuss the physical dispersion relation of surface plasmon polaritons and the Poynting calculation formula of surface plasmon polaritons waveguide from the integral form of Maxwell's equations.two important theoretical models are introduced as well,including coupled-mode and scattering matrix theory,which provide theoretical support for the later text.Then,in the aspect of theory and simulation,the characteristics of the single trapezoid cavity and double trapezoid cavity plasma bandstop filter are discussed.Moreover,the effect of cavity size change on the system transmission spectrum is studied,and the properties of the multi-trapezoid cavity plasma bandstop filter are further analyzed.Finally,combining the above research and analysis,this paper presents a unilateral and double-row plasma bandstop filter with three-trapezoid cavity.These two filters have the characteristics that the range of bandstop filters is easy to tune,and the former is suitable for narrow stopband,while the latter is suitable for wide stopband.Through the simulation calculation of the results based on the finite element method,we draw and compare the results of the simulation data,and attempt to explain the formation of Fano peaks in the transmission spectra of filters.In summary,the research results in this paper have some significance in the field of nano optical communication devices and plasma filters,and provide a theoretical basis for the further design of better plasma filters,which is of positive significance to the design and simulation of micro-nanometer optical communication devices.