本研究的主要目的是深入研究膽固醇液晶（Cholesteric Liquid Crystal, CLC）的相轉變行為，特別是在外界條件變化下（如溫度）對其螺距和旋性變化的影響。膽固醇液晶的螺旋結構隨著溫度改變，進而導致光學性質的變化，如橢圓度的變化。傳統的研究方法，如偏光顯微鏡和穿透光譜測量，雖然能提供宏觀結構信息，但在解析手性結構變化方面存在局限。
為了克服這些技術挑戰，我們提出了基於液晶偏振光柵的圓二色（Circular Dichroism, CD）光譜系統來分析膽固醇液晶的相轉變。CD光譜技術能夠靈敏地檢測手性分子對左旋和右旋圓偏振光的吸收差異，從而提供分子級別的結構變化信息。為了進一步提高測量精度，我們將高解析度單頻CD量測系統整合到動態測量系統中，時間解析度可達5毫秒。這一系統通過有效減少殘留光影響，顯著提高了測量準確性，並能夠捕捉膽固醇液晶在相變過程中的動態結構變化。
本研究不僅為分析膽固醇液晶相轉變過程中的結構重組提供了新的工具，也為顯示技術、生物醫學等領域中手性材料的應用拓展提供了關鍵的數據和理論支持。

The main objective of this study is to investigate the phase transition behavior of cholesteric liquid crystals (CLCs), with a particular focus on the effects of external conditions (such as temperature) on their pitch and chirality. The helical structure of cholesteric liquid crystals changes with temperature, leading to alterations in their optical properties, such as ellipticity. Traditional research methods, such as polarized optical microscopy and transmission spectroscopy, can provide macroscopic structural information but have limitations in analyzing changes in chiral structures.
To overcome these technical challenges, we propose a circular dichroism (CD) spectroscopy system based on liquid crystal polarization gratings to analyze the phase transitions of cholesteric liquid crystals. CD spectroscopy is highly sensitive to the differential absorption of left- and right-circularly polarized light by chiral molecules, thereby offering molecular-level structural information. To further enhance measurement precision, we integrated a high-resolution, single-frequency CD measurement system into a dynamic measurement setup, achieving a temporal resolution of up to 5 milliseconds. This system significantly improves measurement accuracy by effectively reducing residual light interference and can capture the dynamic structural changes of cholesteric liquid crystals during phase transitions.
This study not only provides a new tool for analyzing the structural reorganization of cholesteric liquid crystals during phase transitions but also offers critical data and theoretical support for the application of chiral materials in fields such as display technology and biomedicine.

論文審定書 i
誌謝 ii
摘要 iii
Abstract iv
目錄 v
圖目錄 vii
表目錄 xi
第一章 緒論 1
1.1 前言 1
1.2 研究動機 5
1.3 論文架構 7
第二章 理論分析與文獻回顧 8
2.1 膽固醇液晶 8
2.2 穿透譜和偏光顯微鏡 13
2.3 圓二色效應 16
2.4 液晶偏振光柵 23
2.5 樣品製備 32
2.5.1 洗玻璃 32
2.5.2 水平配向基板 33
2.5.3 膽固醇液晶配置 34
第三章 圓二色系統 37
3.1 系統架設及量測過程 37
3.1.1 溫度控制系統 37
3.1.2 圓二色量測系統 40
3.1.3 穿透譜系統 43
3.1.4 量測系統總結 46
3.2 32%未配向5μm膽固醇液晶量測 48
3.3 32%已配向5μm膽固醇液晶量測 57
3.4 圓二色系統波長限制 62
3.5 結論 64
第四章 不同厚度和濃度膽固醇液晶比較 65
4.1 28%已配向 不同厚度膽固醇液晶 65
4.2 30%已配向 不同厚度膽固醇液晶 70
4.3 不同濃度膽固醇液晶比較 73
4.4 結論 76
第五章 結論與未來展望 77
參考資料 79

[1] Reinitzer, F. Beiträge zur Kenntniss des Cholesterins. Monatshefte für Chemie 9, 421–441 (1888).
[2] P. J. Collings and M. Hird, Introduction to Liquid Crystals Chemistry and Physics. CRC Press, 2017. doi: 10.1201/9781315272801.
[3] Bragg, W. L., & Bragg, W. H. (1913). "The Reflection of X-rays by Crystals." Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 88(605), 428-438
[4] Seeboth, A., & Lötzsch, D. (2013). Thermochromic and Thermotropic Materials. Springer.
[5] W. C. Johnson Jr, “Circular dichroism instrumentation,” in Circular Dichroism and the Conformational Analysis of Biomolecules, Boston: MA: Springer US, 1996, pp. 635–652.
[6] S. K. Teo et al., “Clinical Pharmacokinetics of Thalidomide,” Clin Pharmacokinet, vol. 43, no. 5, pp. 311–327, 2004, doi: 10.2165/00003088-200443050-00004.
[7] C. I. Branden and J. Tooze, Introduction to protein structure. Garland Science, 2012.
[8] X. Wang and Z. Tang, “Circular Dichroism Studies on Plasmonic Nanostructures,” Small, vol. 13, no. 1, p. 1601115, Jan. 2017, doi: 10.1002/smll.201601115.
[9] V. K. Valev, J. J. Baumberg, C. Sibilia, and T. Verbiest, “Chirality and Chiroptical Effects in Plasmonic Nanostructures: Fundamentals, Recent Progress, and Outlook,” Advanced Materials, vol. 25, no. 18, pp. 2517–2534, May 2013, doi: 10.1002/adma.201205178.
[10] B. Ranjbar and P. Gill, “Circular dichroism techniques: Biomolecular and nanostructural analyses- A review,” Chemical Biology and Drug Design, vol. 74, no. 2. pp. 101–120, Aug. 2009. doi: 10.1111/j.1747-0285.2009.00847.x.
[11] J. Xiong, E.-L. Hsiang, Z. He, T. Zhan, and S.-T. Wu, “Augmented reality and virtual reality displays: emerging technologies and future perspectives,” Light Sci Appl, vol. 10, no. 1, p. 216, Oct. 2021, doi: 10.1038/s41377-021-00658-8.
[12] E. Peli and SC. M., “Control of vertically polarized glare,” J Am Optom Assoc, vol. 54, no. 5, pp. 447–450, 1983.
[13] R. Singh, K. N. Narayanan Unni, A. Solanki, and Deepak, “Improving the contrast ratio of OLED displays: An analysis of various techniques,” Opt Mater (Amst), vol. 34, no. 4, pp. 716–723, Feb. 2012, doi: 10.1016/j.optmat.2011.10.005.
[14] H. Chen, G. Tan, and S.-T. Wu, “Ambient contrast ratio of LCDs and OLED displays,” Opt Express, vol. 25, no. 26, p. 33643, Dec. 2017, doi: 10.1364/OE.25.033643.
[15] E. Peli, “Ophthalmic applications of circular polarizers.,” J Am Optom Assoc, vol. 57, no. 4, pp. 298–302, Apr. 1986.
[16] E. Fariza, A. E. Jalkh, J. V. Thomas, T. O’Day, E. Peli, and J. Acosta, “Use of Circularly Polarized Light in Fundus and Optic Disc Photography,” Archives of Ophthalmology, vol. 106, no. 7, pp. 1001–1004, Jul. 1988, doi:10.1001/archopht.1988.01060140147043.
[17] Z. Shaohua, D. Deqiang, L. Wei, R. Ruijian, and D. chen, “Circular polarization modulation technology and its application research in free-space optical communication,” in Second Symposium on Novel Technology of X-Ray Imaging, P. Liu, Y. Tian, and T. Xiao, Eds., SPIE, May 2019, p. 56. doi: 10.1117/12.2524323.
[18] JASCO, “J-1000 Series Models.”
[19] Olis, “DSM Series Models.”
[20] P. Pagliusi, C. Provenzano, A. Mazzulla, L. Giorgini, and G. Cipparrone, “Spectrograph Based on a Single Diffractive Element for Real-Time Measurement of Circular Dichroism,” Appl Spectrosc, vol. 62, no. 5, pp. 465–468, May 2008, doi: 10.1366/000370208784344497.
[21] A. Mazzulla, C. Provenzano, P. Pagliusi, and G. Cipparrone, “Real-Time Circular Dichroism Spectrograph Based on a Single Liquid Crystal Diffractive Element,” Molecular Crystals and Liquid Crystals, vol. 516, no. 1, pp. 233–239, Feb. 2010, doi: 10.1080/15421400903409473.
[22] H. MARGARYAN et al., “DEVICE FOR MEASURING THE CIRCULAR DICHROISM SPECTRUM IN REAL TIME,” Journal of Nonlinear Optical Physics & Materials, vol. 22, no. 04, p. 1350042, Dec. 2013, doi: 10.1142/S0218863513500422.
[23] N. Hakobyan et al., “Technique for Spectropolarimetry Based on Liquid Crystal Polarization Diffraction Grating,” Molecular Crystals and Liquid Crystals, vol. 615, no. 1, pp. 63–69, Jul. 2015, doi: 10.1080/15421406.2015.1068469.
[24] H. Margaryan et al., “Device for real-time measuring of circular dichroism at a specific wavelength,” Journal of the Optical Society of America B, vol. 36, no. 5, p. D66, May 2019, doi: 10.1364/JOSAB.36.000D66.
[25] P. Pagliusi, E. Lepera, C. Provenzano, A. Mazzulla, and G. Cipparrone, “Polarization gratings allow for real-time and artifact-free circular dichroism measurements,” A. Serpengüzel, G. C. Righini, and A. Leipertz, Eds., May 2011, p. 806910. doi: 10.1117/12.886969.
[26] H. Ono, A. Emoto, F. Takahashi, N. Kawatsuki, and T. Hasegawa, “Highly stable polarization gratings in photocrosslinkable polymer liquid crystals,” J Appl Phys, vol. 94, no. 3, pp. 1298–1303, Aug. 2003, doi: 10.1063/1.1587269.
[27] C.-T. Wang, A. Tam, M.-C. Tseng, C.-Y. Lee, T.-H. Lin, and H.-S. Kwok, “Bistable switching of polarization-grating diffractions enabled by a front bistable twisted nematic film,” Opt Lett, vol. 44, no. 2, p. 187, Jan. 2019, doi: 10.1364/OL.44.000187.
[28] C. Provenzano, P. Pagliusi, and G. Cipparrone, “Highly efficient liquid crystal based diffraction grating induced by polarization holograms at the aligning surfaces,” Appl Phys Lett, vol. 89, no. 12, p. 121105, Sep. 2006, doi: 10.1063/1.2355456.
[29] C. Oh and M. J. Escuti, “Achromatic diffraction from polarization gratings with high efficiency,” Opt Lett, vol. 33, no. 20, p. 2287, Oct. 2008, doi: 10.1364/OL.33.002287.
[30] C. Oh, “Broadband polarization gratings for efficient liquid crystal display, beam steering, spectropolarimetry, and Fresnel zone plate,” North Carolina State University, 2009.
[31] M. Honma, E. Uchida, H. Saito, T. Harada, S. Muto, and T. Nose, “Simple system for measuring optical rotation of glucose solution using liquid-crystal grating,” Jpn J Appl Phys, vol. 54, no. 12, p. 122601, Dec. 2015, doi: 10.7567/JJAP.54.122601.
[32] Y. Chen, C.-K. Lee, C.-T. Wang, Y.-B. Cheng, and S.-C. Jeng, “High-accuracy circular dichroism measurement using a liquid crystal polarization grating,” Opt Lasers Eng, vol. 158, 2022, doi: 10.1016/j.optlaseng.2022.107181.
[33] Y. Chen, C.-K. Lee, C.-T. Wang, and S.-C. Jeng, “Development of a compact broadband circular dichroism spectropolarimeter for circular polarizer applications,” Opt Lasers Eng, vol. 163, p. 107480, Apr. 2023, doi: 10.1016/j.optlaseng.2023.107480.
[34] N. Hong and J. N. Hilfiker, “Mueller matrix ellipsometry study of a circular polarizing filter,” Journal of Vacuum Science & Technology B, vol. 38, no. 1, p. 014012, Jan. 2020, doi: 10.1116/1.5129691.
[35] E. Hecht, Optics, 5th ed. Pearson Education India, 2002.
[36] B. E. Saleh and M. C. Teich, Fundamentals of Photonics, 2nd ed. John Wiley & Sons, 2007.
[37] J. W. Lewis, R. A. Goldbeck, D. S. Kliger, X. Xie, R. C. Dunn, and J. D. Simon, “Time-resolved circular dichroism spectroscopy: experiment, theory, and applications to biological systems,” J Phys Chem, vol. 96, no. 13, pp. 5243–5254, 1992.
[38] F. Gori, “Measuring Stokes parameters by means of a polarization grating,” Opt Lett, vol. 24, no. 9, p. 584, May 1999, doi: 10.1364/OL.24.000584.
[39] J. Tervo and J. Turunen, “Paraxial-domain diffractive elements with 100% efficiency based on polarization gratings,” Opt Lett, vol. 25, no. 11, p. 785, Jun. 2000, doi: 10.1364/OL.25.000785.
[40] A. A. Kokhanovsky, Light scattering reviews 4: single light scattering and radiative transfer. Springer Science & Business Media, 2009.
[41] PG De Gennes and J Prost, “The Physics of Liquid Crystals,”,1993.
[42] Satya Prakash Yadav, Shri Singh”Carbon nanotube dispersion in nematic liquid crystals: An overview” Progress in Materials Science, 2016,Elsevier