Researches On Enhanced Transmission And Optical Bistability Effects Based On Surface Plasmon Polaritons In Metal Structures

Surface plasmon polaritons have significant characteristics such as the localized field enhancement, the micro-and nano-scale, and the anomalous dispersion. They have important applications in the material field, the energy field, the biology field, the information field and so on. Specially, surface plasmon polaritons are well applied in the optoelectronic integrated and all-optical integration beyond the interference limitation.In this paper, enhanced transmission and optical bistability effects based on surface plasmon polaritons in subwavelength metal structures are investigated theoretically. Transmission and reflection curves of subwavelength metal structures are further discussed to find potential applications of the designed structures, such as the optical filters, the optical beam splitter and the optical swithes. The main research works are as follows:1. Nobel metal (such as:gold, silver) spherical nanoparticles are used to produce the enhanced transmission effect:Due to the localized surface plasmon interaction among these metal nanoparticles, it shows that the energy can be transferred between the nanoparticles. The nanoparticle arrangement and the polarization of incident light have obvious influences on transmission spectra for a single layer. For the multilayer of metal nanoparticles, the number of the transmission peaks increases with the number of layers increasing. 2. The conditions of Kretschmann configuration generating the optical bistability are discussed by theory. The parameters such as the incident angle and the thickness of the silver film are discussed to find the variation of the reflection curve with the smallest wavelength absorption of silver at1060nm. Evolved Kretschmann configuration is also introduced which is plus a metal film (or a metal grating) with linear medium behind Kerr medium. The evolved structure generates the optical bistability in the transmission and the reflection. The characteristic of the optical bistability in the transmission is also discussed.3. It is analyzed and simulated the structure with the third-order nonlinear medium filling into a nano rectangle hole drilled on a metal film. The results show that the transmission intensities of TE and TM modes changing with incident intensities appear different optical bistability effects. The physical mechanism is well discussed.High lights are as follows:1. The incient polarization, the arrangement and the layer number of this metal nanoparticle array have obvious influences on the tranmission spectra. It provides a possable way to increase or decrease the transmission with a specific frequency.2. Evolved Kretschmann configuration generates the optical bistability in both reflection and transmission. This kind of the structure can be used as a polarization splitter or a beam splitter, which has a potential applications in the splitter in micro-and nano-scale.3. The third-order nonlinear medium is filled into a nano rectangle hole drilled on a cuboid metal film. This structure can generate optical bistability effects for both TE and TM modes. The optical bistability for TE mode is totally different from the one for TM mode. This kind of the structure provides a theoretical basis for the design of the subwavelength splitter.