掃頻式兆赫波光纖化快速影像雷達

由於兆赫波(100GHz - 10THz)產生及偵測技術的蓬勃發展，許多關於兆赫波方面的科學研究都有很大的進步;且近幾年來，兆赫波影像科技方面的相關研究也越來越受到重視。可是，在現今兆赫波影像的研究與應用上，大多是在空氣中利用金屬反射鏡來傳遞兆赫波，使得兆赫波系統變得死板而無法變動。在先進的兆赫波應用來說，對一個依靠性高且簡潔的低損耗傳導物質有非常強烈的需求。另外，因為機械移動速度的限制使得一張二維兆赫波影像的擷取時間通常需要幾分鐘到小時的時間。這使得兆赫波影像技術在需求快速的運用上非常不切實際。因此，我們提出”掃頻式兆赫波光纖化快速影像雷達”，利用快速掃頻的技術取代緩慢的機械移動，在7秒鐘內就可以取得一張二維的兆赫波影像。並且，為了使兆赫波在傳遞的過程中更加的穩定不受外在環境的干擾，整個系統中的兆赫波是由低損耗的次波長兆赫波光纖所架構而成的兆赫波光纖方向耦合器來傳導。除了能夠得到快速的雷達影像外，我們所提出的兆赫波影像雷達同時也可以量測物體的距離或是偵測物體的所在位置，這應該是作為雷達最基本且最重要的特性。雖然7秒鐘得到一張影像對一般雷達運用來說還是顯得緩慢，但以秒為單位的影像擷取時間是可以被人們所接受的，而且相較於一般雷達，我們所提出的兆赫波影像雷達擁有較簡潔的系統架構。

關鍵字

兆赫波；掃頻；兆赫波光纖方向耦合器；兆赫波雷達；兆赫波影像

並列摘要

Since lots of methods for generating and detecting terahertz (THz) had been proposed, various THz scientific investigations were intensively performed. Also, within the last several years, THz imaging technology has been attracting more and more attentions. Amount all the setups of the THz imaging researches and applications nowadays, THz waves are usually conducted by planar or curved metal reflector in free space, which makes the THz system very rigid and vulnerable to environmental disturbance and unreliable. For more advanced THz application with flexible THz system, a reliable and compact guiding structure with low loss is highly desired. Moreover, for a conventional two dimensional THz image, it takes about several minutes to hours due to the slow mechanical movement of the translational stages. This is very unpractical for the daily application. Thus, in this thesis, we proposed the “frequency swept THz fiber-based high-speed imaging radar” which replaced the slow mechanical movement with fast sweeping frequency technique to acquire a two dimensional THz image in less than 7 seconds. To make the whole system be reliable and compact, THz waves were transmitted by the one-point-touched THz fiber-based directional coupler which was constructed by the low loss sub-wavelength PE fiber. As radar, in addition to acquire a fast image, measuring the distance or ranging the object is probably the most magnificent attribute, just like our THz imaging radar does. Although the speed of 7 seconds is still slower than the conventional radar system, the accomplished THz fiber-based imaging radar system has more compact size and an acceptable image acquisition time.

並列關鍵字

Terahertz ； Frequency swept ； THz fiber-based directional coupler ； THz radar ； THz imaging

參考文獻

[2.4] H. -W. Chen, Single mode fiber-based THz directional coupler, M. D. thesis, Institude of Photonics and Electronics, National Taiwan University, Taipei, Taiwan (2006)

[3.7] D. M. Mittleman, M. Gupta, R. Neelamani1, R. G. Baraniuk, J. V. Rudd, and M. Koch, “Recent advances in terahertz imaging,” Applied Physics B 68, 1085 (1999).

[4.6] Alan W. M. Lee and Q. Hu, “Real-time, continuous-wave terahertz imaging by

[4.1] Schottky Diode Detector, Virginia Diodes, Inc., Charlottesville, Virginia (http://www.VADiodes.com).

[1.1] P. H. Siegel, “Terahertz technology, “ IEEE Transactions on Microwave Theory and Techniques 50, 910 (2002).

國際替代計量

掃頻式兆赫波光纖化快速影像雷達

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