Single Ring Structure Of Metallic Resonant Ring In The Terahertz Absorption Characteristics Of The Fdtd Simulation

In this thesis, by changing the metal rings of various parameters, terahertz transmission properties through structures of single-split rings resonance (SRR) are investigated in the far field using THz time-domain spectroscopy system (THz-TDS). And the transmission spectra are simulated based on the finite-difference-time-domain method.The main works are as follows: (1) THz resonance transmission and absorption characteristics of different sizes of single-split rings by changing the metal wire long, metal width and slit width. (2) Application of effective medium theory for the two absorption peaks of the metal ring resonances. And research the root causes of the two absorption peaks. (3) Changes in unit area of the metal ring resonance,and research the structure of transmission and absorption. (4) the transmission spectra of the single-split rings resonance are simulated based on the finite-difference-time-domain method. Our conclusion contains: (1) the metal wire loop length, metal width and slit width has a certain impact on natural frequency of SRR and dipole oscillation absorption. The metal rings of different sizes has the different number of dipole,and result in the location of the oscillating dipole absorption in significant differences. (2) Application of effective medium theory to prove the two absorption peaks of the metal ring resonances, one is comes from double-anisotropic property; the other is comes from anisotropy of the electric dipole. (3) Regardless of the direction of a single ring slit and the incident THz electric field polarized perpendicular or parallel, unit area of metal ring dipole oscillation will affect the location of absorption peak, and with the unit to reduce the size of the metal ring, oscillating dipole absorption peak position moving to the high-frequency. (4) the transmission of the metal ring resonance can be simulated using FDTD method.When the metal ring slit direction and the incident THz electric field polarized are perpendicular, The simulation results correspond well with the experimental results;and when the metal ring slit direction and the incident THz electric field polarized are parallel,not good well with the experimental results. (5) Both cases the transmittance of simulation results were lower than the experimental results. This may be due to the actual metal surface has surface plasmon wave, Makes the transmission enhance.Innovation of this letter is as follows: Theory have a metal ring resonance absorption of the essential reasons for the resonance;found change the size of unit area of metal ring will affect the absorption of the dipole oscillation;and the transmission spectra of the single-split rings resonance are simulated based on the finite-difference-time-domain method. Infections to resonance properties of SRR by terahertz electric and magnetic wave vectors are discussed in this letter. It can be a reference for researching terahertz devices.