Research On Theory And Applications Of Effective Surface Plasmon Polaritons

Surface Plasmon Polaritons are electromagnetic waves propagating along the interface of metal and dielectric at optical frequencies,which have the characteristics of subwavelength confinement,near field enhancement and slow wave.In 2004,J.B.Pendry et al.proposed the concept of Spoof SPPs,and then Hibbins et al.verified the existence of Spoof SPPs in microwave regimes.In 2016,Engheta et al.proposed the concept of Effective SPPs,and our group validated it analytically and experimentally in 2017.In this paper,we carried out theoretical studies and applications on Effective SPPs.The main contexts and contributions are shown as follows:1.The dispersion and transmission characteristics of coupled Effective SPPs mode in a multilayer system have been investigated.The analytical dispersion equations of coupled Effective SPPs mode in the Effective IMI(Insulator / Metal / Insulator)and Effective MIM(Metal / Insulator / Metal)structures in rectangular waveguide and parallel plate waveguide are derived specifically.Analytical and simulation results are in good agreement,and analysis show that these two sandwiched structures resemble nearly the same characteristics of IMI and MIM heterostructures in the optical regime.2.A band-pass filter based on Effective SPPs is designed.The filter is composed of two rectangular waveguides with different lateral widths.Periodical transverse grooves are distributed at the interface of the two rectangular waveguide.The bandwidth of the filter can be flexibly controlled by changing the width of the upper narrow waveguide.Besides,in the bandwidth,the insertion loss of the filter is low.3.Tunneling of Spoof SPPs through Effective ENZ material channel connected with two plasmonic waveguides is proposed.The designed plasmonic waveguide is constructed from dielectric filled rectangular waveguide etched with deep sub-wavelength periodical transverse slots on the upper wall.The tunneling frequency can be flexibly tuned by changing the relative permittivity of the Effective ENZ material and the Spoof SPPs can tunnel efficiently through a straight or an arbitrarily bent Effective ENZ channel with ultra-low loss.