Study On The Properties Of SPPs With Rectangular Aperture Micro-nano Structure Based On FDTD Algorithm

Surface plasmon polaritons(SPPs) are the electromagnetic evanescent waves attenuating exponentially at the metal-dielectric interfaces due to the resonance interaction of the free electrons and the incident photons. SPPs have many outstanding characteristics such as overcoming the conventional diffraction limit, anomalous dispersion relation, near field enhancement, super resolution, subwavelength localization and so on. SPPs have won the widespread application and attention at the corresponding fields. Previous studies on the SPPs with micro-nano structure are based on single hole, hole array, single slit, double slit, slit array, groove, hole surrounded by grooves, grating et al. structures. However, It was found that the intensity of SPPs with single hole structure excited by plane waves was weaker and the reflectivity was also smaller in 1998. So that the later researches have little study on the SPPs with single hole structure. But the SPPs with single hole structure have their inherent and abnormal characteristics and can be used in many fields such as large data storage, photoresist, tunable optical filter, near field enhancement and so on.Therefore, this paper on the field characteristics of SPPs with single rectangular aperture micro-nano structure from theoretical analysis and FDTD simulation has important application value. The main contents of this paper are as follows:(1) According to the thin film waveguide theory, the angular spectrum representations and the frustration total internal reflection of the evanescent waves, we have made the analysis of SPP field representations of the single rectangular aperture micro-nano structure of glass / Au / air three layers structure from the theory aspect.(2) We have used FDTD simulation of the commercial simulation software to make 3D simulation on the tightly focused beam illuminating to the glass / Au / air three layers structure with the single rectangular aperture micro-nano structure and to make 2D simulation on the relations of the transmittance with the key influence factors. The results show that the intensity of SPP generated by the lateral sides of the rectangular aperture along the polarization direction of the incident light is the strongest. As the width of the rectangular aperture along the direction of the incident light polarization is smaller and smaller, the intensity of the SPP generated is the stronger. The transmittance of the glass / Au / air three layers structure with the single rectangular aperture micro-nano structure is dependent on the width of the rectangularaperture along the polarization direction of the incident light.The theoretical analysis results of this paper have some guiding value for the study of the SPPs with other micro-nano structures. At the same time, the simulation results shows the accuracy and reliability. According to the relationship between the transmittance and the key influential factors, the SPPs devices and technologies can be applied to the corresponding fields. In conclusion, the study has the practical referent significance to design micro-nano photonics devices and the near-field enhancement optical components with the extraordinary optical transmission, integrated chips and tunable optical filters.