本篇論文主要透過致發熱的方式發展與研究鐵電型液晶-膽固醇液晶(FLC-CLC)複合材料之元件光學性能表現並發展染料摻雜FLC-CLC雷射器。實驗結果顯示，此元件具有可低電壓、可室溫及可於全白光區域做光子能隙調控，雷射輸出調控可達100 nm範圍。首先本論文量測電致發熱片的溫度響應與FLC-CLC元件於可見光區之反射波段可低電壓調控性，最後探討染料摻雜FLC-CLC雷射器之雷射輸出性質與可電調控性。
本研究摻入鐵電型液晶之優點乃使得整體複合材料之層列-膽固醇液晶相相變溫度提升至室溫附近，讓此元件工作時不需要外加溫控器，另外之優點亦即摻入鐵電性液晶不會影響整體HTP值(使用一般向列型液晶無法取代鐵電型液晶)，透過低電壓(< 2.8 V)可以調控其反射波段的位移在整個可見光區達321 nm，且光子能隙結構仍可保持完整。本研究利用結合Keating model與電致發熱片溫度模型，模擬反射中心波長與外加電壓關係曲線並與實驗結果比較相當擬合。另外，此元件施予電壓從0 V加至2.8 V時，反射波段於整個白光區調控所需時間達150秒，調控速度為2.13 nm/s；在調控性能重複性實驗裡，經過多次(五次)循環之電控反射波段位置並無顯著落差。此外，此論文同時透過給予低電壓(0 V – 0.8 V)可調控染料摻雜FLC-CLC之雷射輸出波長可達100 nm之調控範圍，所得之雷射閥值介於0.21 – 1.38 μJ/pulse之間。

This thesis mainly develops and studies the optical properties of ferroelectric liquid crystal and cholesteric liquid crystal (FLC-CLC) composite devices and further develops dye-doped FLC-CLC (DDFLC-CLC) lasers by means of electrothermal effect. Experimental results show that the device has photonic bandgap (PBG) control in the entire white light region in low-voltage range and at near room temperature, and the spectral range for tuning the lasing wavelength can be as wide as 100 nm. In first part, this study measures the temperature response of the electrothermal heating sheet and the low-voltage regulation of the reflection band of the FLC-CLC device in the visible region. In second part, the properties of the laser output and electrical controllability of the DDFLC-CLC laser are investigated.
The wide tuning of the reflection band (~321 nm) in the entire visible region can be obtained in a low voltage range (0‒2.8 V) with less deformation of reflection band. This study also uses the Keating model and the electrothermal heating model to simulate the relationship between the reflection center wavelength and the applied voltage, which result fits well with the experimental results. In addition, the study also regulates the laser output wavelength of the DDFLC-CLC up to 100 nm in a low-voltage range (0 V – 0.8 V). The lasing threshold of the lasers is between 0.21 – 1.38 μJ/pulse.

1. P. G. de Gennes and J. Prost, The Physics of Liquid Crystals (Clarendon Press, New York, 1993).
2. V. I. Kopp, Z.-Q. Zhang, and A. Z. Genack, “Lasing in chiral photonic structures,” Prog. Quant. Electron. 27, 369416 (2003).
3. Y. Huang, M. Jin and S. Zhang, “Polarization-independent bandwidth-variable tunable optical filter based on cholesteric liquid crystal,” Jpn. J. Appl. Phys. 53, 072601 (2014).
4. K.-H. Kim, D. H. Song, Z.-G. Shen, B. W. Park, K.-H. Park, J.-H. Lee, and T.-H. Yoon, “Fast switching of long-pitch cholesteric liquid crystal device,” Opt. Express 19, 1017410179 (2011).
5. J. Kobashi, H. Yoshida, and M. Ozaki, “Planar optics with patterned chiral liquid crystals,” Nat. Photonics 10, 389393 (2016).
6. I. Ilchishin and E. Tikhonov, “Dye-doped cholesteric lasers: Distributed feedback and photonic bandgap lasing models,” Prog. Quant. Electron. 41, 122 (2015).
7. H. Coles and S. Morris, “Liquid-crystal lasers,” Nat. Photonics 4, 676685 (2010).
8. J.-D. Lin, M.-H. Hsieh, G.-J. Wei, T.-S. Mo, S.-Y. Huang, and C.-R. Lee, “Optically tunable/switchable omnidirectionally spherical microlaser based on a dye-doped cholesteric liquid crystal microdroplet with an azo-chiral dopant,” Opt. Express 21, 1576515776 (2013).
9. L.-J. Chen, J.-D. Lin, S.-Y. Huang, T.-S. Mo, and C.-R. Lee, “Thermally and Electrically Tunable Lasing Emission and Amplified Spontaneous Emission in a Composite of Inorganic Quantum Dot Nanocrystals and Organic Cholesteric Liquid Crystals,” Adv. Opt. Mater. 1, 637643 (2013).
10. Y. Inoue, H. Yoshida, K. Inoue, Y. Shiozaki, H. Kubo, A. Fujii, and M. Ozaki, “Tunable Lasing from a Cholesteric Liquid Crystal Film Embedded with a Liquid Crystal Nanopore Network,” Adv. Mater. 23, 54985501 (2011).
11. T. V. Mykytiuk, I. P. Ilchishin, O. V. Yaroshchuk, R. M. Kravchuk, Y. Li, and Q. Li, “Rapid reversible phototuning of lasing frequency in dye-doped cholesteric liquid crystal,” Opt. Lett. 39, 64906493 (2014).
12. S. M. Wood, F. Castles, S. J. Elston, and S. M. Morris, “Wavelength-tunable laser emission from stretchable chiral nematic liquid crystal gels via in situphotopolymerization,” RSC Adv. 6, 3191931924 (2016).
13. T.-H. Lin, H.-C. Jau, C.-H. Chen, Y.-J. Chen, T.-H. Wei, C.-W. Chen, and A. Y.-G. Fuh, “Electrically controllable laser based on cholesteric liquid crystal with negative dielectric anisotropy,” Appl. Phys. Lett. 88, 061122 (2006).
14. A. Mazzulla, G. Petriashvili, M. A. Matranga, M. P. De Santo, and R. Barberi, “Thermal and electrical laser tuning in liquid crystal blue phase I,” Soft Matter 8, 48824885 (2012).
15. K.-Y. Yu, S.-H. Chang, C.-R. Lee, T.-Y. Hsu, and C.-T. Kuo, “Thermally tunable liquid crystal distributed feedback laser based on a polymer grating with nano grooves fabricated by nano imprint lithography,” Opt. Mater. Express 4, 234240 (2014).
16. S.-T. Hur, B. R. Lee, M.-J. Gim, K.-W. Park, M. H. Song, and S.-W. Choi, “Liquid-crystalline blue phase laser with widely tunable wavelength,” Adv. Mater. 25, 30023006 (2013).
17. H. Yu, B. Tang, J. Li, and L. Li, “Electrically tunable lasers made from electro-optically active photonics band gap materials,” Opt. Express 13, 72437249 (2005).
18. Z.-G. Zheng, B.-W. Liu, L. Zhou, W. Wang, W. Hu, and D. Shen, “Wide tunable lasing in photoresponsive chiral liquid crystal emulsion,” J. Mater. Chem. C 3, 24622470 (2015).
19. H. Bian, F. Yao, H. Liu, F. Huang, Y. Pei, C. Hou, and X. Sun, “Optically controlled random lasing based on photothermal effect in dye-doped nematic liquid crystals,” Liq. Cryst. 41, 14361441 (2014).
20. L.D. Sio, G.Palermo, V.Caligiuri, and C. Umeton, “Electro and pressure tunable cholesteric liquid crystal devices based on ion-implanted flexiblesubstrates,” J. Mater. Chem. C 1, 77987802 (2013).
21. S. S. Choi, S. M. Morris, W. T. S. Huck, and H. J. Coles, “Electrically tunable liquid crystal photonic bandgaps,” Adv. Mater. 21, 3915‒3918 (2009).
22. L. V. Natarajan, J. M. Wofford, V. P. Tondiglia, R. L. Sutherland, H. Koerner, R. A. Vaia and T. J. Bunning, “Electro-thermal tuning in a negative dielectric cholesteric liquid crystal material,” J. Appl. Phys. 103, 093107‒093101 (2008).
23. 田民波 著，林怡欣 校訂，TFT 液晶顯示原理與技術 (五南圖書出版公司，臺灣，2008).
24. J. P. F. Lagerwall, C. Schütz, M. Salajkova, J. H. Noh, J. H. Park, G. Scalia, L. Bergström, “Cellulose nanocrystal-based materials: from liquid crystal self-assembly and glass formation to multifunctional thin films,” NPG Asia Mater. 6, e80 (2014).
25. X. Y. Mu, D. G. Gray, “Formation of chiral nematic films from cellulose nanocrystal suspensions is a two-stage process,” Langmuir 30, 9256-9260 (2014).
26. I. C. Khoo, Liquid Crystals: Physical Properties and Nonlinear Optical Phenomena (John Wiley & Sons, New York, 1995).
27. D.-K. Yang and S. T. Wu, Fundamental of liquid crystal devices (Wiley, 2006).
28. P. Yeh and C. Gu, Optics of liquid crystal displays (John & Sons, Inc., New York, 1999).
29. W.-R. Chen and J.-C. Hwang, “The phase behaviour and optical properties of a nematic/chiral dopant liquid crystalline mixture system,” Liq. Cryst. 31, 1539–1546 (2004).
30. R. B. Meyer, “Effects of electric and magnetic fields on the structure of cholesteric liquid crystals,” Appl. Phys. Lett. 12, 281-282 (1968).
31. F. Castles, S. C. Green, D. J. Gardiner, S. M. Morris, and H. J. Coles, “Flexoelectric coefficient measurements in the nematic liquid crystal phase of 5CB,” AIP Adv. 2, 022137 (2012).
32. N. A. Clark and S. T. Lagerwall, “Submicrosecond bistable electro-optic switching in liquid crystals.” Appl. Phys. Lett. 36, 899-901 (1980).
33. Y. A. Cengel and A. J. Ghajar, Heat and mass transfer (McGraw Hill, 2011).
34. S. Ji, W. He, K. Wang, Y. Ran and C. Ye “Thermal response of transparent silver nanowire/PEDOT:PSS film heaters” Small 10, 4951-4960 (2014).
35. J. J. Bae, S. C. Lim, G. H. Han, Y. W. Jo, D. L. Doung, E. S. Kim, S. J. Chae, T. Q. Huy, N. Van Luan, and Y. H. Lee, “Heat dissipation of transparent graphene defoggers,” Adv. Funct. Mater. 22, 4819-4826 (2012).
36. B. E. A. Saleh and M. C. Teich, Fundamentals of Photonics (John Wiley & Sons, New York, 2007).
37. J. T. Verdeyen, Laser Electronics, 3rd ed. (Prentice Hall, Inc., New Jersey, 1995).
38. 沈柯，雷射原理教程 (亞東書局，臺北市，1990).
39. H. Kogelnik and C. V. Shank, “Stimulated emission in a periodic structure,” Appl. Phys. Lett. 18, 152-154 (1971).
40. A. Yariv and P. Yeh, Photonics, 6th ed. (Oxford University Press, New York, 2007)
41. R. Gupta, K. D. M. Rao, S. Kiruthika, and G. U. Kulkarni, “Visibly transparent heaters,” ACS Appl. Mater. Interfaces 8, 12559-12575 (2016).
42. P. Li, J. G. Ma, H. Y. Xu, D. Lin, X. D. Xue, X. Z. Yan, P. Xia and Y. C. Liu, “Flexible transparent heaters based on silver nanotrough meshes,” J. Alloys Compd., 664, 764-769 (2016).
43. J.-D. Lin, J.-W Lin and C.-R Lee “Low-voltage tunable color in full visible region using ferroelectric liquid-crystal-doped- cholestertic liquid-crystal smart materials,” Proc. of SPIE 10555, 105550B (2018).
44. Y.-C Hsiao, Z.-H Yang, D. Shen and W. Lee “Red, green, and blue reflections enabled in an electrically tunable helical superstructure” Adv. Optical Mater. 6, 1701128 (2018).