我們利用飛秒雷射來激發一個二階非線性晶體(ZnTe)產生THz，且利用電光取樣的方式得知THz電場的時間分布，並藉此用THz來穿透四種不同變因奈米碳管(無雜質的多壁及單壁，以及含雜質的多壁及單壁)得知吸收程度，並利用多重反射的薄膜公式即可計算出奈米碳管的介電常數，因此而得奈米碳管在0.2~2THz的頻譜特性。而由我們的實驗數據看來奈米碳管在THz沒有明顯的吸收，但是含雜質的奈米碳管導電率相對於無雜質的大許多。
我們也有對不同變因奈米碳管作800波長激發-THz探測的實驗，實驗結果顯示可能有兩種不同機制而導致一正一負的訊號產生，我們試著從自由電子遵守的Drude model來解釋其現象。另外也作800波長同色激發-探測的實驗，架設是採取反射式的，實驗結果量測到很明顯的鬆弛現象，我們用Photobleaching(PB)來解釋。

We measured the transmission of THz time domain spectroscopy of four different types carbon nanotubes(pristine multi-wall, single-wall nanotubes, impurity multi-wall, and single-wall nanotubes ).According to our results, there’s no absorption obviously in 0.2~2 THz region, but the conductivity of impurity nanotubes is higher than pristine nanotubes.
We also have measured optical pump-THz probe experiment for different type nanotubes. According to these measurements, there are two different mechanisms, which is exhibits two different scattering times explained by Drude model.
Another 800 pump-probe experiment which is a photoreflectivity (PR) setup will show here. From our data, we found the negative relaxation phenomenon clearly. The negative signals of PR exaplain by Photobleaching (PB).

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