Optical Properties Of Silver Nano-structures And Silver Micro And Nano-spheres Fibers

The surface plasmon resonance （SPR） based evanescent field simulated on thesurface of micro or nano-size metal particles or thin film is very sensitive to theexternal environment and the changes of the parameters of metal structures. Themetal nano-structure can break the diffraction limit in conventional device, andrealize the functions of all-optical modulation, storage, biochemical sensing,nano-particles control and measurement. Furthermore, these devices are inmicro-nanometer dimensions, which is conducive to compact the device on a chip.The main contents in this thesis are listed as follows:The SPR coupling conditions for metal micro and nano-structures are discussed.The SPR dispersion relations and the related characteristic parameters on thesemi-infinite metal-dielectric interface are introduced and derived for P polarizedincident light. Starting from the SPR effect on the surface of nano-layer metal film,the surface reflectance and the resonance absorption peak vs the geometricalparameters of stack multi-metal-dielectric nano-structures and the refractive indexof sorrouding environment are analyzed in detail by theoretical calculation. Thebasic theory of the electromagnetically induced transparency （EIT） likephenomenons based on SPR effects in the metal-dielectric-metal （MDM）nanostructures, comb metal and metal-dielectric nanostructures are discussed, the aswell as the advantages, disadvantages and future trends of traditional EIT and theEIT-like phenomenon in metal micro and nano-structures respectively.A hollow prism model is proposed. The wave vector coupling condition of thisconfiguration is analyzed and discussed in detail. After filling the hollow prism withalcohol and CS₂solution, the corresponding angular distribution of light reflectionspectra are experimentally measured. The significant SPR phenomenon in thereflection spectrum of CS₂solution is observed. The experimental results arediscussed, that is, the light absorption from liquid and the light reflex from SPReffect are compared at different incident angles; By changing the refractive index ofthe measured liquid in hollow prism and the thickness of silver nano-coating-layer,the variation of the SPR resonace absorption peak for different parameters isdiscussed in detail by theoretical calculation; The optical transmissioncharacteristics of the silver-dielectric-silver nano-grating structure with rectangularand triangular single tooth and the optical reflection properties of comb-likesilver-dielectric nano-structures are analyzed through Finite Difference TimeDomain （FDTD） method. The corresponding optical characteristics depend on the parameters of metal-dielectric nano-structures.The silver micro-sphere’s effects on the spectral transmission characteristics ofa hollow fiber with air cone and an hourglass structure fiber are experimetalystudied. The hollow silica fibers with different diameters are prepared by themelting method and the corresponding transmission spectra are measured andcompared; the silver micro-sphere with a diameter of2.3μm is pushed into thehollow cone of silica fiber, meanwhile, the variation of transmission spectra aremeasured and compared for different locations. The experimental results show thatthe intervention of silver micro-sphere leads the changes in both the intensities andpositions of the two transmission resonance peak of hollow fiber taper; The effect ontransmission spectra from the geometric parameters of silver micro-spheres hollowfiber taper and the refractive index of surrounding environment are detaileddiscussed by FDTD simulation.The hourglass quartz fiber structure containing silver nano-spheres of300-500nm in diameter is designed and its spectral transmission characteristics near1550nm are studied. Using ultrasonic oscillation method, one can pour silvernano-particles into a hollow silica fiber and prepared the hourglass quartz fiberstructure within silver nano-particles, whose geometry depends on the diameter ofsilver nano-sphere, the material of fiber, the heating and tension uniformity alongthe fiber during the drawing process. The spectral transmission characteristics of thequartz fiber with hourglass structure are experimental studied. The results indicatethat the SPR and nano-size effect near silver nano-particles hourglass and the airchambers can change the transmission spectra. The transmission spectra of silvernano-particles quartz fiber in different conditons were calculated and studied usingFDTD method, such as the wavelength of incident light, the geometric parameters（the diameters of silver nano-spheres and air chamber） and the refractive index ofsurrounding environment,.The related work above will enrich the research of the metal micro andnano-particles doped fiber optic devices and metal-dielectric nanostructures. Thehollow prism, the quartz fiber with silver micro or nano-spheres and the metalnano-grating structure with EIT-like effect can be applied in optical sensors, lightmodulation and optical memory devices.