Modes and the Fourier Analysis in a Nonlinear Plasmonic Two-Wire Transmission Line

• Main Authors: Liu, Hao Yun, 劉浩雲
• Other Authors: Huang, Chen Bin
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/jymd7z

碩士 === 國立清華大學 === 光電工程研究所 === 105 === We observed two kinds of the fundamental surface plasmon polariton modes in the Two-Wire Transmission-Line (TWTL) and the excited second harmonic generation (SHG) signal both numerically and experimentally. Analyzing the intensity distribution of the spatial Fourier transform of the electric field on TWTL, we tell the difference between the SHG signal excited by two fundamental modes. We use Finite-Difference Time-Domain (FDTD) method in simulation. TWTL is fabricated by focused ion beam on a gold layer deposited on a glass substrate. We use dual-confocal setup to analyze near-infrared (NIR) regime and visible regime (also SHG regime) separately. The laser pulse duration we used as source is 56-fs and the center wavelength is located at 1560-nm. Focused by a 100x objective lens, the laser coupled into the TWTL and reflect back to the NIR confocal system while the transmission wave goes into the visible confocal system. As the results, no matter which polarization we used as source, perpendicular (TE) or parallel (TM) to the TWTL, the excited the SHG signal will always be parallel to the transmission line. Comparing the intensity distribution of the spatial Fourier transform of the electric field on TWTL with the simulation. We ensure that the excited mode by TE or TM modes is exactly TM.