Research On Optical Transmission Phenomena And Mechanisms Of Metal Film -nanoparticle (Hole) Composite Nanostructures

Surface plasmons(SPs) are evanescent waves which are propagated along the metal surface by the interaction of photons and free-electrons. In the area of the sub-wavelength optics, it is an important and long-range regardful issue that regulating the transmission of electromagnetic wave in metal nano-structures in technology and application fields. SPs demonstrate a new vision for controlling and transmitting light. The primary of extraordinary optical transmission(EOT)phenomena was attributed to the excitation of SPPs and LSPs. The phenomenon can provide a new feasible method for applications in highly integrated optoelectronic deviced including tunable plasmonic filters and sensors.In this work, we mainly study the enhanced transmission of subwavelength metal nano-composite structure by using the finite-difference time-domain method(FDTD).We explore the physical mechanism of the phenomenon by changing the parameters of the structure. The main research works are as follows:(1)We have investigated the robust bispectral optical transmission bands in the novel metallic structure consisting of two continuous metallic films inserted with double non-close- packed mutually staggered plasmonic nanoparticle arrays. By varying the diameter of the metallic nanoparticles, the distance between the plasmonic arrays and the metal films, the thickness of the double film, and the gap distance between the double plasmonic nanoparticle arrays, the bispectral enhanced transmission characteristics have been tuned by the cooperative effects of the double mutually staggered metallic nanoparticle arrays and the metal films due to the excitation of near-field plasmon gap modes in the gaps between nanometer separated metallic nano-particles, surface plasmon waves of the metallic films, the resonance transfer of energy between the double plasmonic arrays as well as the formation of optical cavity modes between the double metallic films. The proposed structure with sub-wavelength size can provide a new feasible method for applications in highly integrated optoelectronic devices including transparent conductors, plasmonic filters and sensors.(2) We have investigated the optical transmission properties of the novel metallicstructure consisting of a connected slot antenna plasmonic nanohole array in an Au film. By varying the gap of the metallic nanoholes, the distance of the single aperture, the thickness of the Au film, and the dielectric environment, tunableEOTcharacteristics have been obtained due to the cooperative effects of the excitation of localized surface plasmons(LSPs) around the nanoholes, SPPs on the surface of the Au film, and Fabry–Férot resonances in the nanoholes. These results are significant for specific plasmonic applications and helpful in understanding the mechanisms of EOT phenomena. The proposed structure with subwavelength size can provide a new feasible method for applications in highly integrated optoelectronic devices including tunable plasmonic filters and sensors.