The Splitter Of Surface Plasmon And Several Kinds Of Novel Effects In Subwavelength Metallic Arrays

In this dissertation, we study the two kinds of therotical model for unidirectional excitation of the Surface Plasmon Polartions(SPPs), and a kind of surface plasmon polatitons waveguide splitter. We propose the plasmonic analogy of the discrete Talbot effect in the traditional diffractive optics. We study the transmission characters of two kinds of metallic nano-structure.First, we propose a kind of unidirectional SPPs source based on the single-slit cavity antenna structure. By tuning the central distance between the two metallic films, the excitation intensity and period vary periodically. The period can be explained very well by the theory of Fabry-perot interference. By choosing the suitable parameters, the maximum splitting ratio reaches 24. Thus, this structure can be used as a well unidirectional SPPs source. In addition,we propose another kind of unidirectional SPPs source based on the two-slits cavity antenna structure. Compared with the single-slit cavity antenna structure, its unidirectional excitation is better (the maximum splitting ratio is one order larger than the previous one). Because there is no nano-structre on the transsmion surface, its noise is low. Both of the two SPPs source possess adjustability, good unidirectional and periodical changes for SPPs splitting ratio.Second, we propose a T-shaped metal-insulator-metal (MIM) plasmonic waveguide with a joint cavity, which can manipulate the propagation of SPPs in waveguide. It is found that the SPPs splitting ratio changes periodically as the joint cavity is moved. When the splitting ratio reaches the maximum(or the mimimum), it can be used as a unidirectional excitation device in the plasmonic waveguide. We utilize the scattering matrix to explain the Finite-Difference Time-Domain(FDTD) results well.Third, we propose the discrete SPPs Talbot effect in the subwavelength metal waveguide arrays. Compared with the continuous SPPs Talbot effect, its self-imaging effect has nothing to do with the input period. The Talbot distance can be reduced to subwavelength size. The Talbot distance can be tuned by the thickness of the metallic film and the width of the waveguide. The ultra-short Talbot distance can be reduced to one third of the incident, which is due to the strong coupling between the SPPs in the adjacent waveguides.We calculate the transsmion charators of the subwavelength metallic cavity arrays and slit arrays with single cut by FDTD. For the subwavelength metallic cavity arrays, the transmission peaks originate from the F-P resonance; and the transmission dips originate SPPs resonance. For the compound subwavelength metallic cavity arrays, the transsmion peaks redshift with the increase of the distance between the neighbour cavities. For the subwavelength slit arrays with single cut, the transmission peaks changes with the cut position periodically. The law of the transmission variation can be explained by the transmission line theory very well...