此論文成功證實兆赫波塑膠線波導於微量分子感測應用，從實驗觀察中分析塑膠介質核心的幾何形狀，與其可傳頻率範圍之關係，以及樣品基板中之奈米孔洞結構之必要性，此研究進一步使用磷酸鹽緩衝液為標準樣品，成功取得塑膠線消逝波在各種孔洞尺寸基板之感測能力，並且與彩帶波導比較其感測能力；在同樣的兆赫波頻率與微量分子條件下，塑膠線整合樣品基板之感測靈敏度比彩帶波導載負樣品之感測靈敏度高。基於此塑膠線整合樣品基板之最佳光學條件，可以展現各種顆粒狀與液滴狀分子造成樣品基板之不同波導響應，包括穿透率低值(或是損耗峰值)頻譜偏移，0.3 THz之損耗係數變化，以及等效波導折射係數或是損耗係數之頻譜變化等。此論文成功辨識醣類分子，包括葡萄糖、蔗糖、乳糖等，其感測解析能力約4－7 nmol/mm2左右，也成功辨識鹽類分子，包括海鹽與磷酸鹽兩種，其中感測解析能力約在20－60 nmol/mm2，此外，此波導感測技術法也能夠辨識抗體－抗原分子結合前後之差異。根據等效介質概念，此論文也發展塑膠線波導消逝波波之折射係數感測模型，期望可以從所量測的樣品基板之波導折射係數頻譜，進而可以取得待測分子之本質折射係數頻譜，這是目前所有光學感測技術法中最具挑戰而不容易達到之處，此論文已經從純液體沾附樣品基板之感測實驗中，說明此模型中所需要的樣品條件與其可信度，因此，塑膠線波導之消逝波感測技術法，未來將可以配合不同奈米孔洞尺寸的基板，將極微量的分子呈現可辨識的兆赫頻譜訊號，供應生物、化學等分析用途。

The thesis successfully demonstrates a plastic-wire terahertz (THz) waveguide is workable for sensing the minute molecules. The experimental observation first illustrates the relation between dielectric core geometry and the waveguide spectrum. The sample substrate with nano-porous structure is then revealed as the critical element of the waveguide sensing configuration. Based on the sensitivity calibration with the standard sample of DPBS (Dulbecco's Phosphate-Buffered Saline), various porous substrates are discussed for their sensing abilities while being integrated with evanescent waves of a plastic-wire waveguide. The sensitivity of substrate-integrated plastic wire sensor is also compared with the ribbon waveguides with the porous structures in the study. For the same waveguide frequency and minute amounts of sample, the sensitivity of substrate-integrated plastic wire sensor is higher than that of a ribbon waveguide sensor. Based on the optimal geometry of substrate-integrated plastic-wire sensor, molecules in particles and drops can be recognized from different waveguide properties of the sample substrate, including the spectral shift of transmittance dip (or attenuation peak), attenuation coefficient variation at 0.3 THz, and the variation of effective waveguide refractive indices or attenuation coefficients.

[1] Falconer, Robert J., and Markelz, Andrea G., “Terahertz Spectroscopic Analysis of Peptides and Proteins,” J. Infrared Millim. TE. 33, 973–988 (2012).
[2] E. Castro-Camus, M. Palomar, and A. A. Covarrubias, “Leaf water dynamics of Arabidopsis thaliana monitored in-vivo using terahertz time-domain spectroscopy,” Sci. Rep. 3, 2910 (2013).
[3] P. U. Jepsen, J. K. Jensen, and U. Moller, “Characterization of aqueous alcohol solutions in bottles with THz reflection spectroscopy,” Opt. Express 16, 9318–9331 (2008).
[4] C. Jansen, S. Wietzke, H. Wang, M. Koch, and G. Zhao, “Terahertz spectroscopy on adhesive bonds,” Polym. Test 30, 150–154 (2011).
[5] G. Stewart, and B. Culshaw, “Optical waveguide modelling and design for evanescent field chemical sensors,” Opt. Quant. Electron 26, S249–S259 (1994).
[6] G. Xin, Y. Yibin, and T. Limin, “Photonic Nanowires: From Subwavelength Waveguides to Optical Sensors,” Accounts Chem. Res. 47, 656–666 (2014).
[7] L. J. Chen, H. W. Chen, T. F. Kao, J. Y. Lu, and C. K. Sun, “Low-loss subwavelength plastic fiber for terahertz waveguiding,” Opt. Lett. 31, 308–310 (2006).
[8] B. You, T. A. Liu, J. L. Peng, C. L. Pan, and J. Y. Lu, “A terahertz plastic wire based evanescent filed sensor for high sensitivity liquid detection,” Opt. Express 17, 20675–20683 (2009).
[9] S. Atakaramians, S. Afhar V., T. M. Monro, and D. Abbott, “Terahertz dielectric waveguides,” Adv. Opt. Photonics 5, 169–215 (2013).
[10] Y. S. Jin, G. J. Kim, and S. G. Jeon, “Terahertz dielectric properties of polymers,” Journal of the Korea Physical Society 49, 513–517 (2006).
[11] Y. W. Sun, H. Su, and C. D. Wang, “Dielectric properties of Terahertz windows materials for bio-sample measurement,” World Congress on Medical Physics and Biomedical Engineering, IFMBE Proceedings 39, 661–664 (2013).
[12] B. You, T. A. Liu, J. L. Peng, C. L. Pan, and J. Y. Lu, “Characterization of subwavelength plastic fiber utilizing terahertz time-domain spectroscopy,” Proc. of SPIE 7215, 72150B (2009).
[13] B. You, T. A. Liu, J. L. Peng, C. L. Pan, and J. Y. Lu, “A terahertz plastic wire based evanescent filed sensor for high sensitivity liquid detection,” Opt. Express 17, 20675–20683 (2009).
[14] M. S. Dinleyici, and D. B. Patterson, “Vector modal solution of evanescent coupler,” J. Lightwave technol., 15, 2316–2324 (1997).
[15] S. Zheng, L. N. Binh, and G. P. Simon, “Light coupling and propagation in composite optical fiber-slab waveguide.” J. Lightwave technol. 13, 244–251(1995).
[16] T. F. Tseng, C. H. Lai, J. T. Lu, Y. F. Tsai, and Y. J. Hwang, “Investigation on strong coupling behaviors of THz subwavelength directional couplers.” IEEE Photonics J. 4, 2307–2314 (2012).
[17] H. W. Chen, C. M. Chiu, C. H. Lai, J. L. Kuo, P. T. Chiang, Y. J. Hwang, H. C. Chang, and C. K. Sun, “Subwavelength dielectric fiber-based THz coupler,” J. Lightwave Technol. 27, 1489–1495 (2009).
[18] Y. Ogawa, S. Hayashi, M. Oikawa, C. Otani, and K. Kawase, “Interfernece terahertz label-free imaging for protein detection on a membrance,” Opt. Express, 16, 22083–22089 (2008).
[19] P. C. Upadhya, Y. C. Shen, A. G. Davies, and E. H. Linfield, “Terahertz time-domain spectroscopy of glucose and uric acid”, J. Biol. Phys. 29, 117–121 (2003).
[20] D. K. Lee, J. H. Kang, J. S. Lee, H. S. Kim, C. Kim, J. H. Kim, T. Lee, J. H. Son, Q. H. Park, and M. Seo, “Highly sensitive and selective sugar detection by terahertz nano-antennas,” Sci. Rep. UK 5, 15459 (2015).
[21] Woo-Gi Yi, “Terahertz Spectroscopic Characterization and Imaging for Biomedical Applications,” The Ohin Syate University USA, p.38 (2015).
[22] H. Zhan, S. Wu, K. Zhao, R. Bao, and L. Xiao, “CaCO3, its reaction and carbonate rocks: terahertz spectroscopy investigation,” J. Geophys. Eng., 13, 768–774 (2016).
[23] P. Wang , K. L. Tan, E. T. Kang, and K. G. Neoh, “Plasma-induced immobilization of poly(ethylene glycol) onto poly(vinylidene fluoride) microporous membrane”, J. Membrane Sci. 195, 103–114 (2002).
[24] B. You, and J. Y. Lu, “Remote and in situ sensing products in chemical reaction using a flexible terahertz pipe waveguide,” Opt. Express 24, 18013–18023 (2016)
[25] Y. Li, X. Chen, F. Hu, D. Li, H. Teng, Q. Rong, W. Zhang, J. Han, and H. Liang, “Four resonators based high sensitive terahertz metamaterial biosensor used for measuring concentration of protein,” J. Phys. D: Appl. Phys. 52, 095105 (2019).