Micro/nano Optical Filter Based On The Dependence Of Surface Plasmon On Unit Structure Multiple Geometric Features

Surface plasmon polaritons(SPPs)and local surface plasmon(LSPs)are two forms of surface plasmons(SPs),which have the characteristics of local field enhancement,sub-wavelength and localized field intensity.Therefore,surface plasmons can have a significant impact on the applications of photonic devices,infrared remote sensing and biosensors.With the in-depth study of surface plasmons by scholars,the subject of Plasmonics has gradually been formed.In recent years,the research on the surface plasmons effect produced by hole arrays on metallic thin films and the device design extended by this effect are two important branches in Plasmonics.In this paper,the finite difference time domain(FDTD)method is used to discretize the Maxwell equation,and the whole process of the interaction between light and matter is simulated.The micro-structures of periodic concentrate-core-aperture arrays metal films with multiple geometric characteristics and the transmission characteristics of enhanced optical transmission in the structures were studied.In addition,based on the different resonance modes generated by multiple geometric featuresand their interaction,a novel plasmon optical filter is designed and its feasibility is verified.The main contents are listed as follows:(1)The principle of surface plasmons and the enhanced optical transmission(EOT)phenomenon are demonstrated,and the research background and current situation of this subject at home and abroad are investigated.The discrete Maxwell equation of FDTD method is elaborated in detail,and the settings of light sources,boundary conditions and parameters of experiments are also analyzed.(2)The light transmission processes in different hole arrays(circular,aperture and concentrate-core-aperture arrays)are numerically simulated.The results show that the coupling of resonance modes caused by different geometrical characteristics in the concentrate-core-aperture hole array can transfer the charges generated in the SPPs resonance mode in the inner core to those generated in the LSPs resonance mode in the outer aperture.This results in the interaction between the SPPs resonance mode and the LSPs resonance mode,and then changes the transmission peaks of the two modes in visible and near-infrared bands.(3)Based on the coupling characteristics of different resonance modes generated by multiple geometric features,a novel plasmon optical filter is proposed and designed.In terms of performance,the effects of geometric parameters of different elements on the performance of surface plasmon filters are systematically studied.Simulation results show thatthe performance of plasmon optical filter can be effectively adjusted by changing geometric parameters.Structurally,the filter has the advantages of small size and simple structure,which can make it play a role in integrated circuits and other applications.