本實驗利用飛秒級鈦：藍寶石鎖模脈衝雷射，激發製作於低溫成長砷化鎵基板上之共平面傳輸線以產生兆赫電脈衝，並利用製作於同一基板上之光導開關取樣閘以進行偵測。本實驗主要目的在於：透過準確控制激發光及探測光的光點大小及位置，使光點直徑略小於光導開關受光隙寬度，且光點對稱照射受光隙時，期能產生半高寬極短之兆赫電脈衝。實驗結果發現，在上述情況下，我們偵測到一半高寬僅310飛秒的超短電脈衝，其頻寬大於1兆赫。
本實驗亦探討了當激發光及探測光光點直徑皆略小於光導開關受光隙寬度、且對稱照射受光隙的情形下，改變激發光光點位置對超短電脈衝半高寬的影響。實驗結果發現：當激發光光點中心位於兩共平面傳輸線受光隙中央時，所偵測到的電脈衝具有最窄之半高寬。

同時，為使上述光點聚焦條件較易於實現，我們嘗試利用半導體製程，在一般的共平面傳輸線及取樣閘上製作幾何結構對稱之遮光物以遮蔽光導開關受光隙邊緣的雷射光；此外，藉由製作多個不同尺寸的遮光物，使受光隙照光面積相對改變，相當於降低了調整光點大小的困難度。我們成功地製作出此具有遮光物的共平面傳輸線樣品並且進行量測。結果發現，僅在激發光及探測光皆完全照射光導開關受光隙的情況下，我們量測到一半高寬為960飛秒的電脈衝。

Terahertz electrical pulse correlation with 310 fs FWHM, which corresponds to a 3dB bandwidth larger than 1 THz, was generated by nearly-filled-gap illumination. In the excitation scheme, both optical beams were focused to spot size slightly smaller than the photoconductive gaps and placed within the gaps symmetrically.
With nearly-filled-gap excitation scheme, the dependence on pump beam position of the temporal width of the generated electrical pulses was examined. It is found that the generated electrical pulse is shorter than others when pump beam is positioned at the middle of the gap and placed directly next to the sampling gap.

The processing steps of the partly-shaded coplanar transmission lines is developed. With metal shades added on lines at excitation and sampling sites, it is convenient to implement the nearly-filled-gap excitation scheme. Electrical pulse with 960 fs FWHM was detected from the partly-shaded coplanar transmission lines with both optical beams in filled-gap excitation scheme.

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