本研究利用漸層衰減片對已擴束之雷射光光強度作梯度衰減處理；光強度梯度分佈之雷射光入射摻染料之液晶樣品後產生溝槽深度呈梯度分佈之波紋結構，並利用該結構製作偏振轉換器。
利用此波紋結構製作之偏振轉換器，可將一入射線偏振光轉換成圓偏振光或橢圓偏振光。本研究亦討論偵測光光斑與液晶層厚度之大小對偏振轉換效率的影響。

In this research, the polarization converters were manufactured by impinging intensity-gradient-distribution laser on DDLC (dye-doped liquid crystal) samples, which the gradient distributed light intensity was produced by applying linear variable ND filter.
The performances of these polarization converters were demonstrated, which can convert a linear polarized incident light into a circular polarized light or an elliptic polarized light. The influence of cell gap and beam size of probe beam on the DDLC polarization converter has been discussed.

論文審定書 ------------------------------------------------------------------------------------------i
致謝 --------------------------------------------------------------------------------------------------ii
摘要 --------------------------------------------------------------------------------------------------iii
Abstract ----------------------------------------------------------------------------------------------iv
目錄 --------------------------------------------------------------------------------------------------v
圖次 --------------------------------------------------------------------------------------------------ix
表次 --------------------------------------------------------------------------------------------------xi

第一章 簡介
1.1前言--------------------------------------------------------------------------------------1
1.2液晶簡介--------------------------------------------------------------------------------1
1.2.1 液晶簡介------------------------------------------------------------------------2
1.2.2 液晶分類------------------------------------------------------------------------2
1.3 液晶物理-------------------------------------------------------------------------------5
1.3.1 液晶的光學異向性與雙折射性---------------------------------------------5
1.3.2 溫度對液晶折射率之影響---------------------------------------------------9
1.3.3 液晶的連續彈性體理論----------------------------------------------------10
1.3.4 電場對絕緣向列相液晶的影響-------------------------------------------11
1.3.5 Freedericksz transition---------------------------------------------------------12
第二章 相關理論
2.1 光配向簡介---------------------------------------------------------------------------14
2.1.1 photo-isomerization--------------------------------------------------------14
2.1.2 photo-crosslink--------------------------------------------------------------15
2.1.3 photo-degeneration（or photo-degradation）---------------------------16
2.2 光引致液晶分子轉向效應---------------------------------------------------------17
2.2.1 正力矩效應 - Janossy Model----------------------------------------------17
2.2.2 負力矩效應 - Gibbons Model---------------------------------------------20
2.2.3 吸附引致液晶排列效應----------------------------------------------------21
2.2.4 雷射引致細紋結構（Ripple Structure）----------------------------------22
2.3 光致熱效應---------------------------------------------------------------------------23
第三章 樣品製作與實驗架設
3.1材料特性------------------------------------------------------------------------24
3.1.1 向列相液晶：E7--------------------------------------------------------------24
3.1.2 偶氮染料：Methel Red------------------------------------------------------25
3.2 樣品製作------------------------------------------------------------------------------27
3.2.1 DDLC藥品配製---------------------------------------------------------------27
3.2.2 垂直配向空cell製作-------------------------------------------------------27
3.2.3 充填液晶封口----------------------------------------------------------------29
3.3 實驗架設------------------------------------------------------------------------------29
3.3.1 產生波紋結構架設----------------------------------------------------------30
3.3.2 偏振轉換器檢測架設-------------------------------------------------------33
3.4 實驗相關檢測儀器------------------------------------------------------------------34
3.4.1 偏光顯微鏡（Optical Polarized Microscopy / OPM）------------------34
3.4.2 原子力顯微鏡（Atomic Force Microscopy / AFM）-------------------35
第四章 實驗結果與討論
4.1光引致波紋結構之光強對溝槽深度的影響---------------------------------------37
4.1.1 原子力顯微鏡量測----------------------------------------------------------37
4.1.2 偏光顯微鏡量測-------------------------------------------------------------40
4.1.3 液晶預傾角量測--------------------------------------------------------------41
4.2光斑大小與液晶層厚度對偏振轉換器轉換效率之影響-----------------------43
4.2.1 偏振轉換器效率-------------------------------------------------------------43
4.2.2雷射之光斑大小對偏振轉換器轉換效率之影響-----------------------45
4.2.3樣品之cell gap大小對偏振轉換器轉換效率之影響----------------47
第五章 總結與未來展望
5.1 總結------------------------------------------------------------------------------------48
5.1.1光引致波紋結構之光強對溝槽深度的影響-------------------------------48
5.1.2光斑大小與液晶層厚度對偏振轉換器轉換效率之影響-----------------48
5.2 未來展望------------------------------------------------------------------------------49
參考文獻----------------------------------------------------------------------------------------50

[1] M. Hara, S. Ichikawa, H. Takezoe, A. Fukuda, Jpn. J. Appl. Phys. 23, 1420 (1984).
[2] M. Hara, H. Takezoe, A. Fukuda, Jpn. J. Appl. Phys. 25, 1756 (1986).
[3] I. Janossy, A.D. Lloyd, B. S. Wherrett, Mol. Crys. & Liq. Cryst. 179, 1 (1990).
[4] I. Janossy, L. Csillag, A. D. Lloyd, Phys. Rev. A 44, 8410 (1991).
[5] W. M. Gibbons, P. J. Shannon, S. T. Sun, B. J. Swetlin, Nature 351, 49 (1991).
[6] I. Janossy, T. Kosa, Opt. Lett. 17, 1183 (1992).
[7] G. S. Chen, D. J. Brady, Opt. Lett. 17, 1231 (1992).
[8] A. G. Chen, D. J. Brady, Opt. Lett. 17, 441 (1992).
[9] I. C. Khoo, H. Li, Y. Liang, IEEE J. Quantum Electron. 29, 1444 (1993).
[10] P. G. de Gennes, J. Prost, The Physics of Liquid Crystals, 2nd ed., Clarendon Press, Oxford (1993).
[11] C. W. Oseen, Trans. Faraday Soc. 29, 83 (1933).
[12] H. Zocher, Trans. Faraday Soc. 29, 19 (1933).
[13] F. C. Frank, Discuss. Faraday Soc. 25, 19 (1958).
[14] L. M. Blinov, V. G. Chigrinov, Electrooptic Effects in Liquid Crystal Materials, Springer-Verlag, New York (1994).
[15] W. M. Gibbons, P. J. Shannon, S.-T. Sun, B. J. Swetlin, Nature 351, 49 (1991).
[16] M. Schadt, K. Schmitt, V. Kozinkov, V. Chigrnov, Jpn. J. Appl. Phys. 31, 2155 (1992).
[17] O. Yaroshchuk, L. G. Cada, M. Sonpatki, L.-C. Chien, Appl. Phys. Lett. 79, 30 (2001).
[18] M. Hasegawa, Y. Taira, J. Photopolym. Sci. Technol. 8, 703 (1995).
[19] M. Nishikawa, T. Kosa, J. L.West, Jpn. J. Appl. Phys. 38, 334 (1999).
[20] I. Janossy, A.D. Lloyd, Mol. Cryst. Liq. Cryst. 203, 74 (1991).
[21] I. Janossy, L. Csillag, A. D. Lloyd, Phys. Rev. A 44, 12 (1991).
[22] I. Janossy, A. D. Lloyd, B. S. Wherrett, Mol. Crys. & Liq. Cryst. 179, 1 (1990).
[23] T. V. Galstyan, B. Saad, M. M. Denariez-Roberge, J. Chem. Phys. 107, 9319 (1997).
[24] L. Marrucci, Mol. Crys. & Liq. Cryst. 321, 57 (1998).
[25] T. Kosa, I. Janossy, Opt. Lett. 20, 11 (1995).
[26] E. Santamato, G. Abbate, P. Maddalena, L. Marruvvi, D. Papao, E. Maesera, Mol. Crys. & Liq. Cryst. 302, 111 (1997).
[27] I. Janossy, T. Kosa, Opt. Lett. 17, 17 (1992).
[28] B. Saad, M. M. Denariez-Roberge, T. V. Galstyan, Opt. Lett. 23, 9 (1998).
[29] T. Kosa, P. Palffy-Muhoray, H. Zhang, T. Ikeda, Mol. Crys. & Liq. Cryst. 421, 107 (2004).
[30] F. Simoni, O. Francescangeli, Y. Reznikov, S. Slussarenko, Opt. Lett 22, 549 (1997).
[31] E. Ouskova, Y. Reznikov, S.V. Shiyanovskii, F. Simoni, Phys. Rev. E 64, 051709 (2001).
[32] R. W. Wood, Philos. Mag. 4, 396 (1902).
[33] S. E. Clark, N. C. Kerr, D. C. Emmony, J. Phys. D. Appl. Phys. 22, 527 (1989).
[34] A. E. Siegman, IEEE J. Quantum Electron. 22, 1384 (1986).
[35] S. R. J. Brueck and D. J. Ehrlich, Phys. Rev. Lett. 48, 1678(1982).
[36] H. M. Van Driel, J. E. Sipe, and Jeff F. Young, Phys. Rev. Lett. 49, 1955(1982).
[37] F. Keilmann, Phys. Rev. Lett. 51, 2097(1983).
[38] M. J. Soileau, IEEE J. Quantum Electron. 20, 464 (1984).
[39] R. J. Wilson, F. A. Houle, Phys. Rev. Lett. 55, 2184 (1985).
[40] W. Y. Y. Wong, T. M. Wong, H. Hiraoka, Appl. Phys. A. Mater. Sci. Process. 65, 519 (1997).
[41] J. F. Young, J. S. Preston, H. M. V. Driel, J. E. Sipe, Phys. Rev. B 27, 1155 (1983).
[42] Q.-H. Lu, Z.-G. Wang, J. Yin, Z.-K. Zhu, Appl. Phys. Lett. 76, 1237 (2000).
[43] M. Bolle, S. Lazare, J. Appl. Phys. 73, 7 (1993).
[44] D. W. Berreman, Phys. Rev. Lett. 28, 1683 (1972).