Study About Surface Plasmon Polaritons Through The Periodic Groove Structures In Ag Membrance

In the last decades, with the development of nano-technology and the invention of near-fieldoptical microscopy, an unprecedented transformation is going on in optoelectronics; meanwhile,new interdisciplinary science and research orientations are born all the time. Metallic materialsdraw lots of attentions for their unique physical characteristics, and a new subject namedplasmonics is initiated. Surface Plasmon Polaritons is excited state of evanescent wave, which islocalized in the surface of a metal by the interaction of free-electron and photons. Since theevanescent wave contains the information of the sub-wavelength structure surface, themeasurement of subtle information can be obtained by the detection of the evanescent wave. Themost significant characteristic of evanescent wave is the electric field decays quickly with theincreasing of the propagation distance away from the surface. Therefore, the detection of theevanescent wave should be done in the near-field. Sub-wavelength holes or granule near thesurface of the structures can scatter effectively the evanescent wave, and make it propagate intothe far field.In this paper, according to the two-dimensional finite difference time domain (FTDT)method for the perfect metal and metal, we calculate the transmission distribution of the singleslit surrounded by the sub-wavelength structure by the Fortran programmer, where TM mode ischosen as incident wave which impinges on the sub-wavelength structure. Changing the shapeand the number of the sub-wavelength structure which near the surface of the film, we firstanalyzed the influence of the sub-wavelength structure on the distribution of transmission field,and then analyzed the influence of the number of the grooves on transmission when a lightimpinges on the sub-wavelength slit surrounded by surface grooves. Finally, according to theDrude model, we modify the traditional finite difference time domain, and calculate thetransmission field suitable for Ag.The whole paper is divided into six chapters.The first chapter introduces the research background of the subject, as well as the basictheory and the characteristic length of Surface Plasmon Polaritons. We also introduce differentways of the excitation of Surface Plasmon Polaritons.In chapter 2, we introduce the finite difference time domain method (FDTD) and thecharacteristics of the basic principles discussed in FDTD method, as well as the development and application, give a finite difference time domain method currently used perfectly matched layer(PML) absorbing boundary conditions.In chapter 3, we design the calculation programmer for the transmission of thesub-wavelength slit surrounded by grooves in perfect metal film. By changing the number of thegrooves, the depth of the grooves, the width of the grooves, the periodicity of the grooves, thethickness of the substrate, we research the transmission characteristics of the SPPs in the periodicstructure. By changing the number of the grooves from one to ten, it can influence thedistribution of transmission field. By changing the depth of the grooves, we hold the view thatthe influence of the grooves on transmission because the grooves actually change the storage andre-release of energy at corresponding position. Then we analyzed the influence of the width ofthe grooves, the periodicity of the grooves, the thickness of the substrate is on transmission.In chapter 4, according to the Drude model, we work out the finite difference time domainequations suitable for metal. We calculate the distribution of electric field a when a TM planewave irradiate on a sub-wavelength Ag slit surrounded by grooves on the input surface.In chapter 5, we give a summary of this paper, and put forward the following work.