全息聚合物分散液晶論文：二維全息聚合物-液晶光柵的制備研究

1、全息聚合物分散液晶論文：二維全息聚合物/液晶光柵的制備研究【中文摘要】全息聚合物分散液晶(Holographic polymer dispersed liquid crystals, HPDLCs)光柵作為一種新型的光學(xué)元件,在計量、無線電天文學(xué)、集成光學(xué)、光通信和信息處理等許多領(lǐng)域都有著十分廣泛的應(yīng)用。傳統(tǒng)的光柵都是一維的結(jié)構(gòu),是通過將制備好的樣品在兩束相干涉光束的光場處曝光,使光敏單體在水平方向上聚合形成相互平行的等寬度等間隔的結(jié)構(gòu),在樣品中只記錄了一個光柵；本文中研究的二維光柵可以同時在樣品中記錄兩個光柵結(jié)構(gòu),相當(dāng)于在樣品中同時記錄了正交的兩個一維光柵結(jié)構(gòu),其制備方法是將混合均勻的光敏單

2、體材料和液晶注入液晶盒中,在雙束激光干涉處使樣品曝光一段時間,然后將樣品旋轉(zhuǎn)90度,再曝光一次,使光敏單體在兩個方向上聚合得到。二維光柵在光入射時形成的衍射圖樣是空間點陣,除上述的應(yīng)用之外還可以用于光互聯(lián)中的分束器,調(diào)制器和耦合器件等,拓寬了光柵的應(yīng)用范圍。雖然二維全息聚合物分散液晶光柵的應(yīng)用很廣泛,但是目前的制備方法還不成熟,還存在很多問題,主要是光聚合反應(yīng)中相分離不完全,衍射效率偏低,光柵驅(qū)動電壓過高,器件穩(wěn)定性差等。本文首先對實驗體系所用的液晶、化學(xué)材料進(jìn)行選擇和研究,分析光聚合反應(yīng)中的光引發(fā)劑的化學(xué)重排過程,研究聚合物與液晶相分離機(jī)理；其次,通過改變光照時間、光強(qiáng)等參數(shù)、研究各組分在光

3、聚合中所起的作用和影響,增加光聚合的反應(yīng)程度,以得到具有清晰的相分離結(jié)構(gòu)和較高衍射效率的二維聚合物液晶光柵；再次,依據(jù)對衍射效率影響因素的分析,選擇不同作用的添加劑,提高光反應(yīng)效率,提高相分離程度；文中選擇了含氟單體材料和增塑劑DOP來改善光柵形貌,以提高光柵的衍射效率,降低光柵的驅(qū)動電壓；最后,通過設(shè)計和改進(jìn)光路,通過兩次曝光法制備了具有良好相分離界面,具有較高衍射效率和較低驅(qū)動電壓的二維聚合物液晶光柵。最后對光路進(jìn)行調(diào)整,制備了小周期的二維的聚合物液晶光柵。【英文摘要】Holographic polymer dispersed liquid crystals (HPDLCs) gratin

4、gs as a novel optical components,have a very wide range of applications in the measurement, radio astronomy, integrated optics, optical communication, information processing and many other areas.The traditional grating is one-dimensional structure and prepared by beam exposure in two-beam interferen

5、ce field to make the photosensitive monomer polymerization in the horizontal directionz and form the equal-distance and equal-interval stripe parallel to each other.and only records one grating. A two-dimensional grating researched in this article can be simultaneously recorded two gratings in the s

6、amples, is equivalent to simultaneously recorded a orthogonal structure of the two one-dimensional grating in the sample. The method to prepare two-dimensional grating is mixed photosensitive monomer into the liquid crystal material and then injected into the sample cell. Put it into two-beam interf

7、erence field and make it exposure.after 15s rotate 90 degrees and make it exposure another until the photosensitive monomer polymerization completely in the horizontal and the vertical direction of the sample. The diffraction pattern formed by two-dimensional grating is the space lattice when the in

8、cident light go through the cell, Besides the application of the above.it can be used for the beam splitter of optical interconnection, modulators and coupling devices, broaden the scope of application.Although the application of two-dimensional holographic polymer dispersed liquid crystal grating i

9、s comprehensive, but the preparation method is not mature, there are still many problems at present. Mainly the phase separation is not complete in the polymerization, low diffraction efficiency,and the drive voltage is too high, poor device stability.The liquid crystal and chemical materials used i

10、n the system are selected and studyed first in this experimental.and then analyzed the chemical rearrangement process of polymerization photoinitiators.and study the phase separation mechanism of polymer and liquid crystal. Secondly.study the role and impact of each component by changing the irradia

11、tion time, light intensity and other parameters in the photopolymerization, in order to increase the degree of photopolymerization and obtain the two-dimensional diffraction polymer/liquid crystal grating with clear separation structure and higher efficiency. Thirdly, based on the analysis to the fa

12、ctors influenced diffraction efficiency, chose different additives to improve the efficiency of light reaction and improve the degree of phase separation. In this paper fluorinated monomers and plasticizer DOP are to selected to improve the grating morphology and the diffraction efficiency, and redu

13、ce the driving voltage.Finally, we design and improve the optical path to prepare the two-dimensional polymer/liquid crystal grating with good separation interface, high diffraction efficiency and low driving voltage by two exposure method. At last,we improve the optical path to prepare a two-dimens

14、ional polymer /liquid crystal grating with small period.【關(guān)鍵詞】全息聚合物分散液晶 衍射效率 驅(qū)動電壓 相分離【英文關(guān)鍵詞】Holographic polymer dispersed liquid crystal Diffraction efficiency Drive voltage Phase separation【目錄】二維全息聚合物/液晶光柵的制備研究摘要4-5ABSTRACT5-6目錄7-9第一章 緒論9-161.1 液晶簡介91.2 全息聚合物/液晶光柵9-131.2.1 全息聚合物分散液晶9-101.2.2 研究全息聚合物

15、/液晶光柵的意義10-111.2.3 全息聚合物/液晶光柵的結(jié)構(gòu)及工作原理11-131.3 全息聚合物/液晶光柵的發(fā)展及現(xiàn)狀13-151.4 論文研究目的和內(nèi)容15-16第二章 全息聚合物/液晶光柵的材料及相分離的研究16-362.1 引言162.2 制備聚合物/液晶光柵的材料的選擇16-192.2.1 液晶材料的選擇16-172.2.2 單體材料的選擇17-182.2.3 光引發(fā)劑的選擇18-192.3 聚合物/液晶光柵的制備19-212.4 聚合物/液晶光柵的電光特性21-232.4.1 光柵衍射特性21-232.4.2 驅(qū)動電壓232.5 聚合物/液晶光柵的形成及相分離機(jī)理研究23-282.5.1 引言23-252.5.2 液晶/單體相分離理論分析及動力學(xué)擴(kuò)散過程25-282.6 全息二維光柵28-352.6.1 實驗光路的設(shè)計28-292.6.2 實驗?zāi)M29-352.7 小結(jié)35-36第三章 全息聚合物/液晶光柵的制備36-573.1 曝光強(qiáng)度對光柵影響36-403.1.1 實驗36-373.1.2 結(jié)果與討論37-403.2 不同曝光時