Design And Research Of Filter And Sensor Based On Surface Plasmon

With the rapid development of communication technology,modern society puts forward higher requirements for the accuracy of information and the integration of communication devices,optical communication technology using light as carrier shows great potential.Compared with the electron,since the photon has stronger stability,faster speed and lower energy consumption,it is inevitable that the photonic devices will gradually replace the traditional electronic communication equipment.As two basic and important photonic devices in the field of optical communication,filters and sensors have been widely concerned by researchers.Because the surface plasmon has the characteristics of breaking the diffraction limit and the localization of photons,so as to achieve the control of photons in the micro nano scale,the design of micro nano optical filter and refractive index sensor based on surface plasmon has become a research hotspot.The following is a brief introduction to the research content of this paper:Firstly,the research background and significance,the research progress of surface plasmons,micro nano photonic devices such as filters and sensors,and the research status are introduced;Secondly,the basic theory of surface plasmon is discussed.The metal Drude dispersion model is analyzed,and the dispersion relations of surface plasmons in metal insulator and metal insulator metal multilayer interface are calculated.The coupled mode theory,finite difference time domain method and finite element method are studied;Thirdly,two kinds of basic structures,i.e.the tooth cavity and the bilateral coupled resonator,are studied.By using the coupled mode theory,the tooth cavity structure is analyzed theoretically.According to the circular and rectangular resonator structures,a high-performance band-pass filter is designed,and the sharp Fano peak is excited by adjusting the parameters and expanding the size,so that the structure has excellent sensing characteristics at the same time;Finally,two kinds of filter and sensor based on double rectangular cross coupling structure are designed.By studying the filter structure of T-shaped resonator,a new Fano resonance peak is excited by destroying the vertical symmetry of the rectangular cavity,which makes it have both filtering and sensing characteristics.Next,this paper innovatively proposes a bilateral coupled cross cavity sensing structure,and extends the cross cavity structure by coupling the ring cavity at the bottom,and five sharp Fano resonance peaks appear.The structure has very high sensitivity(1478 nm/RIU)and FOM value(5×105),which has important reference value for the application of high performance refractive index sensor.