Study Of The Surface Plasmon Filter Based On The Structure Of Rectangular Resonator Waveguide

Understand and how to control the interaction between light and the matters,has always been the target which researchers dreaming to resolve, and it is also one ofthe crucial issues in the field of science and technology. Surface Plasmon Polaritions(SPPs), which are waves propagating along a metal-dielectric interface with anexponentially decaying field in both sides, are caused by the coupling of free electronand photon on the metal surface. By altering the structure of a metal’s surface, themodes, coupling effect, dispersion relation, propagation way and other properties ofSPPs can be significantly changed. The unique nature of SPPs makes it play a vitalrole in many phenomena of the interaction between light and metal structure ofsubwavelength, and it is become the current hot spots of near-field optics andcondensed matter physics. By studying these phenomena, people can control thepropagation of light using metal conductors, which would promote the researchprogress of optical storage technology, optical devices, bio-photonics, component andcircuit of SPPs, plasmonic chips, renewed light source, microscopy, nano-waveguideand nano-electronic devices, and so on. In this paper, aimed at the opticalcharacteristics, dispersion and propagation as well as the artificial control of metalstructure of surface Plasmon subwavelength, we used the two-dimensionalfinite-difference time-domain method (FDTD) to carry out a comparative systemsresearch. The main results are summarized as follows:By altering the geometry and the material parameters of the metal gratingstructures, we theoretically studied the directional excitation of subwavelengthsurface Plasmon using one dimensional grating coupling method. The research hasshown that by changing the cycles, depth and width of the grating, we can make lightwith different wavelength deflect toward different direction at the output of thegrating. Concretely speaking, when the wavelength of light is516.96nm, the SPPsdeflect toward right at the output of the grating; while, when the wavelength of lightis827nm, the SPPs deflect toward left. When different structures of the grating aremade in and out of a metal, the grating in the metal can increase the strength of theSPPs. This method provides a theoretical basis for the design of nano-electronicdevices, such as sensors, optical integrated circuit, and it has been applied to theoptical communications, plasma light source, optical printing techniques and otherrelated fields. Basing on the structure of metal-dielectric-metal(metal-insulator-metal, MIM)rectangular resonator, we have presented a new type of surface Plasmon band-stopfilter in this article. This structure consists of a waveguide channel and a column ofrectangular cavity resonator which is parallel to the waveguide. When F-P conditionsare met between the length of the rectangular cavity and the wavelength, the surfacePlasmon (Surface Plasmon Polaritons, SPPs) of the wavelength will be restricted inthe cavity, but other light with different wavelength can pass, then resulting to thefiltering effect. By adjusting the length and the number of the resonator, we can easilyfilter out one or more specific single wavelength. Compared to the other structures ofSPPs filter, this structure is more concise, can filter narrower wavelengths and withsmaller energy loss. It can be applied to simpler optical equipments in high integratedcircuit devices. Two-dimensional finite-difference time-domain method (2-D FDTD)simulations were performed to elucidate the properties of the device.