本實驗於兆赫茲時域頻譜量測系統上，以釐米級之金屬元件重整兆赫茲電磁輻射波形。本研究利用不同直徑的金屬圓孔與圓擋板、金屬刀片以及細銅線，分別將各金屬元件置放於大孔徑光導天線後方進行實驗量測，觀察兆赫茲電磁輻射波形變化之現象。從不同直徑的金屬圓孔實驗結果得知，當圓孔直徑為 2 mm 時強度比值約為1，但圓孔直徑大於 2 mm 時低頻與高頻的強度比值會大於 1，而直徑越大的圓擋板則會增加低頻與高頻的強度比值。金屬刀片實驗結果顯示當發射器的遮蔽面積越大時高頻訊號會有明顯的衰弱，因此由以上實驗結果得知超快雷射照射於大孔徑光導天線時，其中央處分布為較高頻的兆赫茲輻射波。依據以上的實驗結果，我們嘗試以實驗方式作出一個能波形重整且有兆赫茲輻射波高穿透率之細銅線元件結構，並針對細銅線元件的排列方向，作 0° 與 90° 之量測，90° 的實驗結果與原參考波形相似，但在 0° 時元件結構對於 0.8 THz 以下的兆赫茲輻射波有衰弱之現象，頻率越低衰減越大，而高於 0.8 THz 時就有著
近似於 1 的穿透率，其類似於高通濾波器之特性。此金屬結構元件具有高頻兆赫茲輻射波的高穿透率，並相對於原參考波形有較寬的半高寬，因此將此元件應用於兆赫茲時域頻譜技術上，可增加量測系統的應用性與獲得更多的資訊。

This study employs the technique of terahertz (THz) time-domain spectroscopy (TDS) and the emitter is a largeaperture photoconductive antenna. We use millimeter dimensional metal devices to realize the spatial distribution of radiation frequency from THz wave emitter and the transmittance of THz wave depended on the orientation of the polarizing device. The amplitude ratio of 0.2 THz to 0.8 THz increases with the diameter of metal hole and the blocking area with the circular metal plate. In the knife-edge experiment, the high frequency (0.6 THz) peak drop rapidly as covering the center area. Thus the low frequency component is dominant for the emitter and the intensity of high frequency component substantially reduces with the divergence angle. The polarizing device is composed of several commercial copper wires to collocate above a metal hole. THz wave propagates through the polarizing device without signifi cant power loss when the orientation of wires perpendicular to the polarization of THz wave. For the parallel case, the polarizing device exhibits the characteristic of a high-pass fi lter. The transmittance increases with frequency below 0.8 THz and closes to 1 over 0.8 THz. Therefore, the polarizing devices can reshape the THz waveform and provide a convenient means to manipulate the resonance features of THz wave.