| In this thesis,symmetrical hybrid plasmonic waveguide,graphene modulator and SERS substrate based on SPPs are studied.The development and application of traditional SPPs in various fields has been hindered due to the large propagation loss.Hybrid plasmonic waveguide(HPW)have attracted a lot of attention in the scientific community because of its high light confinement without suffering large loss.Therefore,we designed a symmetrical HPW based on finite element method,and conduct a detailed theoretical analysis on the propatation characteristics of HPW.Graphene has attracted a lot of attention because of its excellent photonic and opto-electronic properties,such as strong light graphene interaction,broadband operation,ultra-high carrier mobility and high light transmittance.Therefore,the electro-optic modulation based on graphene has developed rapidly.We analyzed a hybrid plasmonic waveguide with TE and TM mode separately located in different regions,and rationally designed a high-performance TE graphene optical modulator to optimize its performance by adjusting the height of the ridge width and the low refractive index layer.The performance of graphene was further analyzed including insertion loss,modulation depth,bandwidth and quality factor for the given optimal device structure.Finally,the operation wavelength range of the modulator was analyzed.The near-field and far-field behavior of SPPs play a great role for breaking through surface-enhanced Raman spectroscopy(SERS)technology.The triangular array and nano-firework substrates were designed with gold nanoparticles as materials.The near-field enhancement with the excitation wavelengths and structure sizes was analyzed.It was found that the near-field enhancement of the substrate was closely related to the excitation wavelength and the nanoparticle spacing.Triangular arrays and nano-fireworks structures have excellent enhancement at specific excitation wavelengths,with the high average field enhancement in the gap region.Finally,the far field characteristics of nano-fireworks were analyzed,and the energy gathering ability of far-field is analyzed. |
