Font Size: a A A

Surface Plasmon Resonance Characteristics Of Metal Nanostructures

Posted on:2013-06-22Degree:MasterType:Thesis
Country:ChinaCandidate:J J WuFull Text:PDF
GTID:2248330374988710Subject:Optics
Abstract/Summary:PDF Full Text Request
Surface plasmons (SPs) are an electronic density wave which is propagated along the surface of a metal by the interaction of free-electrons and photos. In a certain condition, surface plasmon resonance will be realized in metallic nano structure, which makes metallic nano structure have some particular optical properties, like high localized and intensified electric field and extraordinary optical transmission, etc. It has a widespread use in Nan optics, optoelectronics, like it can be used to make optical filter, light switch, couplers, and optical antennas and so on. This paper mainly investigates the optical property, regulation mechanism and related application of several metallic nano structures.Our main work is listed as below:1. Metallic slit arrays with Y-shaped channels are proposed and their transmission properties are investigated numerically using FDTD method. Results indicate that the surface plasmon resonance peak value keeps unchanged and the localized waveguide resonance peak red-shifts and falls obviously when the entrance slit width narrows. However when the entrance slit becomes extremely small the surface plasmon resonance peak red-shifts and falls sharply. Furthermore as the slit length increases, firstly the surface plasmon resonance peak splits into two peaks, then the right peak value rise and finally they slowly converged into one single peak. To understand its physical origin, surface plasmon resonance and Fabry-Perot cavity resonance theories are suggested. Their electric field distributions are simulated and find the electric fields become stronger as the slit become narrower or the dielectric constant become smaller. The results may be useful for the design of optical filter and other optical devices.2. Metallic slit arrays of straight channels with perpendicular cuts are proposed and their transmission properties are investigated numerically using FDTD method. Results indicate that there are four high order F-P resonance modes in our considered region. Compared with smooth straight channel, the cut in the middle of the slit makes odd F-P resonance mode red shift and even F-P resonance mode blue shift. Increasing the width and depth of the cut has similar influence as above, but the transmission property is more sensitive to depth than to width. Also plot the electronic distributions versus the wavelength of the resonance peak are plot to explain the simulation results. Finally the influence of dielectric in the cut on the transmission property is studied. The results may be useful for the design of optical switch.3. Periodic metallic triangle optical nan antennas arrays are proposed and their optical properties are investigated numerically using FDTD method. Results indicate:there are some regular resonance peaks in the range of visible light besides of many resonance peaks on the right of the band gap. Enhanced electric field is localized in the triangle vertex and it is distributed in a quadrupole pattern.The charge oscillations of electric quadruple are source of near field electromagnetic radiation. As the gap between the left and right triangle increase, the left resonance peak will keep in the same wavelength, but the peak will decrease and finally disappear until the gap is25nm. Also series of resonance peaks in the right move to longer wavelength and their value decrease, so a wide band gap is formed in the left. Finally the effect of dielectric constant on the transmission property of the nan antennas is investigated. The results have a guiding role in the design of optical nan antennas.
Keywords/Search Tags:surface plasmons, localized waveguide resonance, extraordinary optical transmission, sub wavelength periodic structure, optical nan antennas
PDF Full Text Request
Related items