本篇論文中我們在藍相液晶中加入不同的偶氮材料並討論其光電特性及應用。實驗主要分成三部分，第一部分為將偶氮苯液晶(Azobenzene liquid crystal, 簡稱Azo LCs)摻雜於藍相液晶中，在UV雷射照射後藍相液晶會因同分異構化反應而發生等溫相變(isothermal phase transition)過程，最後轉變成各向同性態(isotropic phase)。另由UV光照射而呈現各向同性的液晶樣品可藉由照射綠光或放置一段時間的方式再次變回藍相狀態。第二部分為將左旋偶氮苯旋性物質(chiral azobenzene dopants) 摻雜於藍相液晶中，因左旋偶氮苯旋性物質的特性會與右旋的手性分子(CB15)相互抵銷，而藍相需在高旋性的膽固醇液晶中形成雙螺旋結構才會出現，故在未照射UV光時，樣品為膽固醇液晶，而照射UV光後，左旋偶氮苯旋性物質對液晶之HTP值會相對減少，換言之其旋性變高，最終使藍相出現。而UV光照射而呈現藍相的樣品可藉由加熱的方式使左旋的偶氮苯旋性物質之HTP完全回復。故加入偶氮苯液晶照光可使狀態由藍相轉變為各向同性相再轉回藍相；而加入偶氮苯旋性物質則藉由照光或加熱使狀態由膽固醇相轉變為藍相再轉回膽固醇相。第三部分為偶氮苯液晶摻雜於藍相液晶中的應用，主要是製作出藍相與各向同性相週期分佈之相位光柵，並探討其光電特性。

In this study, the studies of electro-optical characteristics of the azobenzene materials doped blue-phase liquid crystal (BP-LCs) are reported. The thesis consists of three parts. The first part is the investigation of the isothermal phase transition from blue phase to isotropic phase by photoisomerization effect resulted from the irradiation of UV light in azobenzene liquid crystals (azo LCs)-doped BP-LCs. Additionally, the isotropic phase can be transferred back to blue phase rapidly by green light-illumination or slowly by nature relaxation. Second, we successfully demonstrate the phototunable textures between cholesteric LCs (CLCs) and BP-LCs in azo chiral-doped CLCs. The key mechanism is the optically controllable effective chirality of the azo chiral-doped CLCs, resulted from the competition between the right- and left-hand chirality in azo chiral-doped CLCs following illumination by specific types of light. Experimentally, the effective chirality, which results in blue phase (CLCs) can be increased (decreased) by UV-illumination (yellow laser-illumination or heating). Finally, it is also demonstrated that periodical phase gratings with periodic modulation of blue phase and isotropic phase in azo LCs-doped BP-LCs. Such phase gratings are optically addressable, thermally/optically erasable, optically re-addressable and electrically switchable.

[1] W. M. Gibbons, P. J. Shannon, S. T. Sun and B. J. Swetlin, Nature 351, 49 (1991).
[2] H. K. Lee, A. Kanazawa, T. Shiono and T. Ikeda, Chem. Mater. 10, 5 (1998).
[3] J. H. Liu and H. Y. Wang, Journal of Applied Polymer Science 91, 789 (2004).
[4] T. H. Lin, Y. Huang, Y. Zhou, Andy Y. G. Fuh and S. T. Wu, Opt. Express 14, 4479 (2006).
[5] H. Yoshida, C. H. Lee, Y. Miura, A. Fujii and M. Ozaki, Appl. Phys. Lett. 90, 071107 (2007).
[6] S. Kurihara, S. Nomiyama and T.Nonaka, Proc. SPIE, 4107 (2000).
[7] S. Kurihara, Y. Hatae, T. Yoshioka, M. Moritsugu, T. Ogata and T. Nonaka, Appl. Phys. Lett. 88, 103121 (2006).
[8] A. G. Chen and D. J. Brady, Opt. Lett. 17, 441 (1992).
[9] T. V. Gastyan, V. Drnoyan and S.M. Arakelian, Phys. Lett. A, 217, 52 (1996).
[10] F. Simoni, O. Francescangeli, Y. Reznikov and S. Slussarenko, Opt. Lett. 22, 549 (1997).
[11] H. Kikuchi,Yokota M., Y. Hisakado, H. Yang and T. Kajiyama, "Polymer-stabilized liquid crystal blue phases," Nature Materials, 1 64 (2002).
[12] Naoki Tanaka, Nikkei Microdevices, "Blue Phase:Samsung's Revolutionary' LCD Discussed", SID, May 27 (2008).
[13] 松本正一, 角田市良 ”液晶 之基礎與運用”(台北市,國立編譯館, (1996).
[14] 液晶應用技術研究會 編著, “最新液晶應用技術”(建興出版社, 1997).
[15] 顧鴻壽 編著, “光電液晶帄面顯示器－第二版”(新文京開發出版社, 2004).
[16] Peter J. Collings and Michael Hird, “Introduction to Liquid Crystals Chemistry and Physics”, Taylor & Francis Ltd, Hampshire (1997).
[17] D. Statman, E. Page, V. Werner and J. C. Lombardi, Phys. Rev. E 75, 021703 (2007).
[18] C.-R. Lee, T.-S. Mo, K.-T. Cheng, T.-L. Fu and Andy Y.-G. Fuh, Appl. Phys. Lett. 83, 4285 (2003).
[19] O. Francescangeli, S. Slussarenko and F. Simoni, Phys. Rev. Lett. 82, 1855 (1999).
[20] F. Reintzer, Monatsh. Chem. 9, 421 (1888).
[21] Letter from F. Reintzer to O. Lehmann, reported by H. Keller, Mol. Cryst. Liq. Cryst. 21, 1(1973).
[22] R. Hochgesand, H. J. Plach, and I. C. Sage, “Helical Twisting Power of Chiral Dopants in Nematic Liquid Crystals”, technical report by E. Merck and BDH Chemicals Ltd. (1989).
[23] A. Yariv, “Optical Electronics in Modern Communications” ,Oxford University Press, New York, (1997).
[24] A. Yariv, “Quantum Electronics”, Wiley, New York, (1988).
[25] H.-S. Kitzerrow, C. Bahr, " Chirality in Liquid Crystals", Springer, New York (2001).
[26] B. Bahadur, " Liquid Crystals : Applications and Uses ", Vol.1, World Scientific, Singapore (1990).
[27] N. A. Clark and S. T. Lagerwall, Appl. Phys. Lett. 36, 899 (1980).
[28] I. C. Khoo and S. T. Wu, “Optics and Nonlinear Optics of Liquid Crystals ”, World Scientific, Singapore, (1993).
[29] M. Marinelli and F. Mercuri, Phys. Rev. E 61, 1616 (2000).
[30] M. Marinelli and F. Mercuri, Phys. Rev. E 61, 1616(2000).
[31] 朱自強, 王仕璠, 蘇顯渝 編著, 現代光學教程, 四川大學出版社, 成都, (1990).
[32] Jun Li, Sebastian Gauza, and Shin-Tson Wu, J. Appl. Phys. 96, 19 (2004)
[33] P. G. de Gennes and J. Prost, “The Physics of Liquid Crystals”, Oxford University Press, New York, (1993).
[34] 謝葆如, 藍相液晶顯示材料(工業材料雜誌270期).
[35] H. Kikuchi, "Liquid crystalline blue phases," in Liquid Crystalline Functional Assemblies and Their Supramolecular Structures. 128, 99 (2008).
[36] C. Bohley, "Polarization optics of periodic media,"Ph.D. thesis, University of Neuchatel (2004).
[37] Shin-Ying Lu and Liang-Chy Chien, Optics letteer. 35, 4 (2010).
[38] P. P. Crooker, "The blue phases - a review of experiments," Liquid Crystals. 5, 751 (1989).
[39] H. S. Kitzerow, "Blue phases come of age: a review," Proceedings of the SPIE - The International Society for Optical Engineering. 7232, 723205 (2009)
[40] Linghui Rao, Zhibing Ge and Shin-Tson Wu, "Emerging blue phase liquid crystal displays", Proc. of SPIE. 7775 77750Y-1 (2010).
[41] H. J. Coles and M. N. Pivnenko, Nature. 436, 997 (2005).
[42] A. G. Chen and D. J. Brady, Opt Lett. 17, 441 (1994).
[43] I. C. Khoo,Hong Li and Yu Liang, Opt Lett. 19, 1723 (1994).
[44] P. G. de Gennes and J. Prost,”The physics of liquid crystals”. 2nd ed.
[45] P. Yeh, Introduction to Photorefractive Nonlinear Optics, John Wiley & Sons, New York (1993).
[46] U. A. Hrozhyk, S. V. Serak, N. V. Tabiryan, and T. J. Bunning, Mol. Cryst. Liq. Cryst. 454, 235 (2006).
[47] Quan Li, Lisa Green, Nithya Venkataraman, Irina Shiyanovskaya and Asad Khan, J. Am. Chen. SOC (2007).
[48] Chun-Ta Wang, Hu-Yi Liu, Hsin-Hui Cheng, and Tsung-Hsien Lin, Appl. Phys. Let . 96, 041106 (2010).
[49] D. K. Yang and P. P. Crooker, Phys. Rev. A. 35, 192 (1987).