Study On The Mode Coupling And The Switching Characteristic In Metal/dielectric Multi-layer Grating Structures

The excitation and coupling of surface plasmon polaritons (SPPs) are an importantresearch field of nanophotonics in metallic micro-nano structure. Through control themodes coupling, the manipulation of optical properties of the structure can be achieved.In this paper, we study the mode-coupling and optic-controlling properties ofmetal/dielectric structure with grating modulation. First of all, in dielectric/metal/airstructure, the influence on the structure resonance characteristics is discussed, of thegrating modulation, grating period and incident angle. Reflectivity and field distributionare given numerically. By introducing of symmetry, we show the influence of incidentangle on the resonance characteristics of dielectric/metal/dielectric symmetric structure.On this basis, increase the structural unit, study on the properties of excitation andcoupling mode of double periodic metal/dielectric multilayer structure. And using thecoupled oscillator model to explain the coupling effect of SPP modes and cavity modes.By introducing the nonlinear material in metal/dielectric structure, we calculatethe bistability and switch characteristics. In order to reduce the switching thresholdvalue, metal and dielectric complex with a high3-order nonlinear coefficient has beenchosen as the nonlinear material. We realize numerically the on-off of the reflection andtransmission on the resonance frequency via controlling the refractive index of thedielectric layer by controlling the on-off of the pump light. Firstly, we discuss theall-optical switching properties with single period metal/dielectric structures. Twodifferent circumstances of vertical and oblique incidence has been considering. In orderto obtain switch with multi-wavelength control, we increase the number of unit structure.The switching characteristics of doubly periodic metal/dielectric multilayer structureare calculated, and all-optical switching with multi-wavelength in the ultraviolet andvisible light band can be achieved.