應用光導天線於兆赫波產生及量測系統開發

Abstract

本研究架設了兆赫波時域頻譜系統，利用飛秒雷射作為光源，並使用光導天線為發射端，接收端的部分則使用光導天線和電光偵測器兩種不同的裝置來進行實驗。當使用光導天線為接收端時，我們量測到165皮秒的訊號，當使用電光偵測器為接收端時，我們量測到1.5皮秒的訊號，並利用傅立葉轉換得到頻譜為4 THz，另外我們做了外加不同偏壓和雷射光強的訊號比較，得出場強和偏壓以及雷射光強的相依關係，最後將樣品的放置位置整合進量測系統，並期望之後能在生物檢測和材料檢測上有所幫助。

We set up terahertz time domain spectroscopy (THz-TDS), using femtosecond laser as light source and using photoconductive antennas as emitter. We also use photoconductive antennas and electro-optic sampling to be receiver. When we use photoconductive antennas to be receiver, we detect the signal which the pulse duration is 165 ps. When we use electro-optic sampling to be receiver, we detect the signal which the pulse duration is 1.5 ps, and the spectrum is 4 THz by Fourier transform. We also compare the pulses with different bias voltage and optical power, and the amplitude of radiation field depends on bias voltage and optical power. Final, we put the sample location to the terahertz measurement system. We expect to apply to bio-sensing and inspection of material in the future.