Coupling and propagation of surface plasmon resonance on waveguide of Au nano-rod
Date Issued
2007
Date
2007
Author(s)
Huang, Hung-Ji
DOI
zh-TW
Abstract
The interaction of light with nano-sized metallic structures results to driving oscillations of collective free electrons on the surface of the metal, called surface plasmon resonance (SPR). Waveguides based on SPR can provide strong guidance of light via periodic metallic structures, metallic particle chains or metallic nano-rods in nano-optical system. Many research efforts are devoted to obtain the optical properties of metallic nano-rods. Optical extinction spectroscopy, scanning near-field optical microscopy (SNOM) and far-field Raman scattering by methylene blue are utilized to characterize the SPR on Au or Ag nano-rod. Since gold nano-rods can function as fundamental building blocks in plasmonic integrated optics, it is crucial to know their individual optical properties, especially the relationship between the incident light and the induced SPR modes on each single nano-rod.
In this paper, to avoid the complexity of SNOM and the influence caused by the probe, we use simple polarization-contrast microscopy to attain far-field images of a single gold nano-rod. In particular, we find out the wave vectors of the induced longitudinal SPR modes from a gold nano-rod for its individual optical properties. Modulated standing modes resulted from the interference of longitudinal SPR modes and incident light are observed. By counting the average distance of adjacent beats on this single gold nano-rod, the wave vector of longitudinal SPR modes can be obtained. We found a linear relationship between the wave vectors of the incident light and the induced SPR modes. Experimental results demonstrate a feasible way on acquiring plasmonic optical properties from an individual single gold nano-rod. Instead of using gold nano-rods with various sizes, we utilize the same single gold nano-rod for the measurements to obtain its individual optical properties. Our experiments can be very useful for acquiring the individual optical properties of gold nano-rods or similar fundamental building blocks in complicated nano-devices of plasmonic nano-photonics.
“TiO2 thin film coated optical fiber” (TTF-fiber) is a good media for transmission and allocation of light to induce photocatalytic reaction. Understanding the optical effect of the TTF-fiber is very important and benefit the optimized design for highest operation efficiency. In this paper, exponential decay rate of propagation light in TTF-fiber is calculated by beam propagation method (BPM). We can also obtain thickness of TiO2 thin film that reaches highest operation efficiency for the light source of UV-LED as well.
We compare the difference on exponential decay rate of propagation light with various thicknesses of TiO2 on TTF-fiber. It shows that the Cu doping is not only change the energy level of TiO2 but also increase its metallic behavior. The surface plasmon resonance can be induced on the TiO2 thin film and increase the light-harvest efficiency. Therefore we can have Cu doped visible-light photocatalysis.
Subjects
表面電漿震盪
奈米金棒
表面電漿積體光學
偏振對比顯微術
紫外光發光二極體
二氧化鈦光觸媒光纖
可見光光觸媒
surface plasmon resonance
Au nano-rod
plasmonic nano-photonics
polarization-contrast microscopy
UV-LED
photocatalytic fiber
visible-light photocatalysis
SDGs
Type
thesis
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