Research On Surface Plasmon Enhancement Magneto-optic Effect

In recent years,the surface plasmon resonance(SPR)effect has been widely used in fields such as information communication,medicinal chemistry,and biosensors.The maturity of micro-nano processing technology allows researchers to design more nanostructures on the surface of the magneto-optical film,and use the surface plasmon resonance to enhance the magneto-optical effect,thereby expanding the application scope of magneto-optical devices and research direction of magneto-optical surface plasmon(MOSPR).In addition to using SPR properties to enhance magneto-optical performance,the related properties of MOSPR can also be adjusted by controlling the size and direction of the external magnetic field.Therefore,it is necessary to research on MOSPR devices detailed.Compared with metal magneto-optical materials,dielectric magneto-optical materials have the advantages of low loss and high magneto-optical performance,so they are used to prepare magneto-optical isolators,magneto-optical modulators and other communication equipment.Traditional nano-technology has the characteristics of high cost and low efficiency,which hinders the research of surface plasmon devices.To solve these problems,a hexagonal periodic Au nanohole MOSPR device was fabricated on Ce: YIG/YIG/Si multilayer film structure by PS nanosphere self-assembly method in this paper.The wave vector of incident light is matched with the SPP wave vector,which directly excite the SPP mode on the surface of the hole structure.The COMSOL software simulation near-field analysis shows that the two SPP modes of the MOSPR device originate from the coupling mode generated between Au and the upper and lower dielectric,and its transverse magneto-optic Kerr effect(TMOKE)enhancement mainly comes from the of pure optical effects.The albumin from bovine serum(BSA)bioprotein sensing experiments of MOSPR devices show that the sensing FOM of TMOKE spectrum is twice as high as that of SPP mode.At the same time,an EBL system was used to prepare the split ring resonators(SRR)metasurface on the magneto-optical film of Ce: YIG,and the reflection of the devices was measured by an ellipsometer.The relationship between the incident polarization state and the reflection spectrum is studied.The excitation conditions of the magnetic resonance are that the polarization direction of the incident electric field is perpendicular to the opening of the SRR structure.Using COMSOL to conduct near-field analysis of the electrical resonance mode and magnetic resonance mode of the SRR structure,it was found that a strong field local effect appeared at the opening of the SRR structure under magnetic resonance conditions,and an induced magnetic field perpendicular to the plane was generated.SRR-structured magneto-optical metasurfaces have great research value in enhancing magneto-optical effects and magnetic field-regulated metasurface properties.