A Study On Beam Splitting Device Based On Surface Plasmonic Polaritons Waveguides

The optoelectronic devices based on surface plasmon polaritons have some special performances for example small size,fast speed and being able to overcome the characteristics of light diffraction,which provide new ways for the study of Micro-Nano Photonics sub-wavelength devices.In this paper,different spectral devices are designed based on the resonance effect of surface plasmon polaritons in the noble metal and silver layer.The transmission properties of the surface plasmon polaritons on the surface of the device are studied by finite element method.Firstly,the surface plasmon polaritons is excited by the groove-like defects on the surface of the metal film.According to the interference effect of the surface plasmon polaritons in the propagation process,three kinds of optical beam splitter of the sandwich waveguide structure based on the dielectric and metal film are designed which are able to achieve the function of the beam splitting of the propagating surface plasmon polaritons.The Si₃N₄-Ag-Si waveguide structure has poor beam splitting effect on surface plasmon polaritons excited by 694.3nm,and the beam splitting effect of Au-Si₃N₄-Au and AuSi₃N₄-Ag waveguide is better,And the Au-Si₃N₄-Ag waveguide structure has a higher transmission distance.Finally,based on the sandwich structure of dielectric and metal film layer,the surface plasmon polaritons waveguide optical demultiplexer of Si₃N₄-Ag-Si and Au-Si₃N₄-Ag are designed to realize the surface plasmon polaritons excited by 694.3nm and 753.1nm wavelengths being able to have the function of derivative.By designing different groove defects and optimizing the width of the grooves,surface plasmas polaritons excited by two different wavelengths can be propagated to different side of the groove,and then transmitted through the terminal coupling to realize the splitting of two wavelengths lights.