在一般「液晶-聚合物」混合薄膜元件調控是利用外加電壓來達成操控元件的目的，但是在近兩年之間發展出一種新的技術，其特點是利用施加在「液晶-聚合物」薄膜元件外部的切應力達到調控元件的目的，這種技術稱為—應力調製液晶，利用這種技術的「液晶-聚合物」薄膜元件具有許多特性，其中又以快速反應與較大的相位延遲最為重要。本篇論文利用應力調製液晶元件的快速反應特性製作出應力調製液晶光柵元件。在元件進行施加應力後，聚合物對液晶作用達到均勻配向，同時亦降低遲滯作用的影響，並具有很大的相位差(在25μm的元件厚度下可達到7π)。本論文同時利用光罩製作液晶-聚合物光柵元件，光柵元件結構在受到應力調製後會再曝光強弱不同區域結構變化有差異，即形成一種應力可調變光柵元件繞射光強度及偏振，同時此種光柵元件在這些調變特性皆可應用在很多光學系統中。外加不同電壓可改變繞射結果，對特定繞射階數增強或減弱，而且亦可調製繞射光偏振態。

A liquid crystal-polymer composite film device is generally controlled with application of a voltage. In the past two years, a new technology of fabricating a liquid crystal-polymer film has been developed. This new technology is called “Stressed Liquid Crystal (SLC)”. The key feature of SLCs is that it can be tuned by stressing the substrates. Fast response and large phase retardation can be achieved using a SLC device. In this paper, we utilize the fast response characteristic of SLC devices to make tunable beam steering devices (SLC gratings). After shearing, polymer network formed in the film produces uniform alignment of the liquid crystal domains, and reduces the hysteresis in Transmission vs. Voltage curve at the same time. A SLC film can achieve a large phase retardation(about 7πfor a 25μm thick cell). Experimentally, a SLC grating is fabricated using a photomask. When a shearing force is applied on a SLC grating device, the strong and weak polymer network formed in bright and dark zones have different strength to align liquid crystals. This allows use to tune both the intensity and polarization of the diffracted beams. Moreover, the grating diffractions of a stressed SLC grating can be electrically switched. The tunability of the intensity and/or the polarization of the diffracted beams for a grating is highly demanded in various optical systems. Thus, SLC gratings have potential for practical applications.

[1] P. G. de Gennes and J. Prost, "The Physics of Liquid Crystals", Oxford University Press, New York (1993), Second edition, Chap. 2.
[2] 松本正一、角田市良"液晶之基礎與應用",復文書局(1991)
[3] P. J. Collings and M. Hird 原著, 楊怡寬, 郭蘭生, 鄭殷立 編譯, "液晶化學及物理入門" , 偉明圖書 第一版(2001)
[4] M. Blinov and V.G. Chigrinov, "Electroopic Effects in Liquid Crystal Materials", Springer-Verlag, New York (1994)
[5] F. Reintzer, Monatsh. Chem, 9, 421(1888)
[6] Latter from F. Reintzer to O. Lehmann, reported by H. Keller, Mol. Cryst. Liq. Cryst. 21, 1(1972)
[7] J.L.Fergason, Society for Information Display (SID) International Symposium Digest of Technical Paper 16, 68(1985)
[8] J.W.Doane,A. Vaz, B-g. Wu and S. Zummer,Appl. Phys. Lett, 48, 269 (1986)
[9] J. West, Mol. Cryst. Liq. Cryst. 157, 427 (1988)
[10] R. L. Sutherland, SPIE proc. 1080, 83 (1989)
[11] B.-G. Wu, J. H. Erdmann and J. W. Doane Liq. Cryst. 5, 1453 (1989)
[12] C. Kittel and H. Kroemer, "Thermal Physics", W. H. Freeman and Company, San Francisco (1980), Second edition, Chap. 2.
[13] I. C. Khoo , "Liquid Crystals", John Wiley & Sons, New York(1995)
[14] I. C. Khoo and S. T. Wu, "Optics and Nonlinear Optics of Liquid Crystal", World Scientific, Singapore(1995)
[15] S.T. Wu, D.K. Yang, "Reflective Liquid Crystal Displays", JOHN WILEY & SONS, LTD，New York（2001）p.162-174
[16] 黃啟炎，「液晶聚合物薄膜之光學二倍頻現象研究」， 國立成功大學博士論文，中華民國八十六年九月
[17] 葛聰智，「聚合物-液晶混合材料在全像光柵應用之研究」， 國立成功大學博士論文，中華民國八十五年六月
[18] Paul S. Drzaic, Liquid Crystal Dispersions, "World Scientific, Singapore" (1995)
[19] G. P. CrawFord and Zumer, "Liquid Crystal in Complex Geometries" , Taylor, London (1996)
[20] S. T. Wu and D. K. Yang, "Reflective Liquid Crystal Displays" , Wiley, New York (2001).
[21] P. Sixou, C. Gautier, and H. Villanova, "Nematic and cholesteric PDLC elaborated under shear stress" , Mol. Cryst. Liq. Cryst. 364, 679-690 (2001)
[22] T. -C. Ko, Y. –H. Fan, M. –F. Hsieh, Andy Y. -G. Fuh, C. –Y. Huang, M. –S. Tsai and I. –M. Jiang, "Diffraction from polymer-stabilized cholesteric texture films", Jpn. J. Appl. Phys., 40, 2255-2258. (2001)
[23] Andy Y. -G. Fuh, M. -S. Tsai, C. -R. Lee and Y. -H. Fan, "Diffraction from a one-beam generated hologram on a polymer-dispersed liquid crystal film", Opt. Commun. 167, 53 (1999)
[24] Andy Y.-G. Fuh and T.-H. Lin, "Electrically switchable spatial filter based on polymer-dispersed liquid crystal film", J. Appl. Phys. 96, 5402-5404. (2004)
[25] 林宗賢，「液晶空間濾波元件之研究與應用」， 國立成功大學博士論文，中華民國九十五年六月
[26] 林靜蘭，「利用聚合物混合液晶薄膜製作溫度感應器」， 國立成功大學碩士論文，中華民國八十三年六月
[27] 陳國忠，「不同紫外光偏振方向硬化之液晶-聚合物混合薄膜之光學特性影響」，國立成功大學碩士論文，中華民國八十八年六月
[28] 吳欣聰，「摻雜高介電常數材料之液晶-聚合物混合薄膜光電特性研究」，國立成功大學碩士論文，中華民國八十九年六月
[29] John L. West, Guoqiang Zhang, and Anatoliy Glushchenko, "Stressed Liquid Crystals for Electrically Controlled Fast Shift of Phase Retardation" SID Digest, 34, 1469-1471 (2003)
[30] John West, Ke Zhang, Matt Zhang, Toshihiro Aoki, Anatoliy Glushchenko. "Stressed liquid crystals" Proc. SPIE, 5741, 10,(2005)
[31] Y. H. Wu, Y. H. Lin, H. Ren, X. Nie, J. H. Lee, and S. T. Wu "Axially-symmetric sheared polymer network liquid crystals " Opt. Express 13, 4638-4644 (2005).
[32] Y. H. Wu, Y. H. Lin, Y. Q. Lu, H. Ren, Y. H. Fan, J. R. Wu and S. T. Wu "Submillisecond response variable optical attenuator based on sheared polymer network liquid crystal" Opt. Express 12, 6377-6384 (2004)
[33] Y. H. Fan, Y. H. Lin, H. W. Ren, S. Gauza, and S. T. Wu "Fast-response and scattering-free polymer network liquid crystals for infrared light modulators " , Appl. Phys. Lett. 84, 1233-5 (2004)
[34] San-Yi Huang, Shing-Trong Wu and Andy Ying-Guey Fuh, "Optically switchable twist nematic grating based on a dye-doped liquid crystal film", Appl. Phys. Lett. 88, 041104(2006)