| In the thesis, the polarization depended on transmission of terahertz (THz) pulses through sub-wavelength hole arrays on a metal foil is investigated experimentally and theoretically. The enhanced transmission spectra are measured by the terahertz time-domain spectroscopy system and are simulated based on the finite-difference-time-domain method. The simulation results are in good agreements with the experimental observations and the mechanism of the enhanced transmission is explained. The main results are as follows:1. Phenomena of the enhanced THz transmission through one layer or two layers of hole arrays on a metal foil are investigated It was demonstrated that these transmission spectra are in possession of frequency-selective characteristics.2. The transmission spectra of the circular hole arrays, square hole arrays, and circular plus square hole arrays are investigated. It was found that the transmission spectrum of the circular plus square hole arrays is not equal to the sum of the circular hole arrays and the square holes array.3. The polarization of the THz beam tlirougli one layer and two layers of the hole arrays on metal foil are investigated. For the symmetrical samples, the THz transmission spectra are independent of the incident polarization. However, for the asymmetrical samples, the transmission spectra depended on the polarization of incident THz wave.In summary, the polarization depended on transmission of THz pulses tlirougli sub-wavelength hole arrays is investigated theoretically and experimentally, and the underlying physical mechanism behind the effect of the extraordinary THz transmission is explained. It will provide a significant reference for the design of photonic device in the terahertz region. |
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