Design And Preparation Of The Two-Dimensional Periodic ?-Shaped Metal Plasman Resonance Structure

Surface plasmon resonance is a kind of special optical properties, which is formed by photons and free electrons on aprecious metal surface.Surface plasmon resonance peak positions can be effectively adjusted by changing the sizes, shapes and assembling ways of metal nanostructures to meet our requirements. In recent years, the surface of metal nanostructures plasma optical has broad application prospects in photocatalysis?optical sensing?biomarkers?medical imaging?solar cells, as well as surface enhanced Raman spectroscopy and other fields.Due to the limitation of nano fabrication process, it is very difficult to achieve both economic and efficient deep subwavelength plasmonic structure. According to anisotropic etching properties of 100 crystalline silicon, a type of V-shape metal surface Plasmon resonant structure with the angle of 54.7° has been designed. Based on the finite element analysis (FEA) method and COMSOL Multiphysics simulation software, the field enhancement factors of rectangle, trapezoid plasmon resonant unit and periodic trapezoidal grating have been compared and analyzed. Results show the Fano resonance results in a further field enhancement with the enhancement factor of around 2000 magnitude when the grating period matches the resonance of the unit.Based on the simulation results, the two dimensional V-shape metal surface plasmon resonant structures were manufactured by methods such as electron beam lithography (EBL), ultraviolet light moment, magnetron sputtering coating and silicon processing technology. Due to the highly matured traditional silicon processing technology and sputtering coating technology, the space between the V-shape slot can be accurate and stably controlled, which provides a reproduced and controllable ultrasmall gap compared with other nanostructures fabrication methods.The two-dimensional grating of the periodic metal surface Plasmon resonant structure realize a fano resonance caused by the coupling of surface Plasmon resonance and localized surface Plasmon resonance. Also, the 2D sharp edge extends the detection range from a single point to a line, achieves a higher field enhancement and a larger field enhancement scope, which guarantee the target molecules pass the localized field enhancement area of the detection unit senstively and accurately. This structure has important applications in high precision sensor detection, such as untagged single molecule Raman detection.