Liquid Crystal Diffraction Gratings Using Photocrosslinkable Liquid Crystalline Polymer Films as Alignment Layers

  • Tomoyuki Sasaki
  • Kohei Noda
  • Hiroshi Ono
  • Nobuhiro Kawatsuki


We report liquid crystal (LC) diffraction gratings fabricated using photocrosslinkable liquid crystalline polymer (PLCP) films for alignment layers of low-molecular-weight nematic LCs. In our PLCP films, the mesogenic molecules were oriented axis-selectively by irradiating them with linearly polarized (LP) ultraviolet (UV) light followed by annealing at the LC temperature. The optical anisotropy caused by the molecular orientation was relatively high. The orientation direction was controlled by the exposure energy of LP UV light and the polarization direction. PLCP films are transparent in the visible region of the spectrum and are thermally stable. This means that they are suitable for various optical applications. PLCP films with uniaxial alignment are applicable for use as alignment layers for low-molecular-weight LCs. Using PLCP films with a periodic orientation distribution, we can fabricate LC diffraction gratings that have high diffraction efficiencies, various polarization conversions, and can be switched with the application of external fields. We will then summarize our recent studies on photoalignment techniques of PLCP films and LC diffraction gratings with photoregulated PLCP films.


Liquid crystal Photocrosslinkable liquid crystalline polymer Photoalignment Diffraction grating Polarization control 


  1. Barachevsky VA (1991) Photoanisotropic polymeric media and their application in optical devices. Proc SPIE 1559:184–193CrossRefGoogle Scholar
  2. Batalioto F, Bechtold IH, Oliveira EA, Evangelista LR (2005) Effects of microtextured substrates on the molecular orientation of a nematic liquid-crystal sample. Phys Rev E 72:031710CrossRefGoogle Scholar
  3. Chandrasekhar S (1992) Liquid crystals. Cambridge University Press, New YorkCrossRefGoogle Scholar
  4. Chen J, Bos PJ, Vithana H, Johnson DL (1995) An electro-optical controlled liquid crystal diffraction grating. Appl Phys Lett 67:2588–2590CrossRefGoogle Scholar
  5. Choi H, Wu JW, Chang HJ, Park B (2006) Holographically generated twisted nematic liquid crystal gratings. Appl Phys Lett 88:021905CrossRefGoogle Scholar
  6. Crawford GP, Eakin JN, Radcliffe MD, Jones AC, Pelcovits RA (2005) Liquid-crystal diffraction gratings using polarization holography alignment techniques. J Appl Phys 98:123102CrossRefGoogle Scholar
  7. Duffy WL, Hindmarsh P, Kelly SM, Owen GJ (2001) An investigation of the role of cross-linking and photodegradation of side-chain coumarin polymers in the photoalignment of liquid crystals. Chem Mater 13:694–703CrossRefGoogle Scholar
  8. Ebralidze TD, Ebralidze NA (1992) Hologram record by means of film anisotropy photoinduction. Appl Opt 31:4720–4724CrossRefGoogle Scholar
  9. Emoto A, Ono H, Kawatsuki N, Uchida E (2005) Polarization gratings in photocrosslinkable polymer liquid crystals prepared using two-step ultraviolet exposure. Jpn J Appl Phys 44:535–538CrossRefGoogle Scholar
  10. Emoto A, Wada T, Shioda T, Sasaki T, Manabe S, Kawatsuki N, Ono H (2011) Vector gratings fabricated by polarizer rotation exposure to hydrogen-bonded liquid crystalline polymers. Jpn J Appl Phys 50:032502CrossRefGoogle Scholar
  11. Fabbri F, Garrot D, Lahlil K, Boilot JP, Lassailly Y, Peretti J (2011) Evidence of two distinct mechanisms driving photoinduced matter motion in thin films containing azobenzene derivatives. J Phys Chem B 115:1363–1367CrossRefGoogle Scholar
  12. Gibbons WM, Shannon PJ, Sun ST, Swetlin J (1991) Surface-mediated alignment of nematic liquid crystals with polarized laser light. Nature 351:49–50CrossRefGoogle Scholar
  13. Gwag JS, Fukuda J, Yoneya M, Yokoyama H (2007) In-plane bistable nematic liquid crystal devices based on nanoimprinted surface relief. Appl Phys Lett 91:073504CrossRefGoogle Scholar
  14. Honma M, Nose T (2003) Polarization-independent liquid crystal grating fabricated by microrubbing process. Jpn J Appl Phys 42:6992–6997CrossRefGoogle Scholar
  15. Honma M, Nose T (2004) Liquid-crystal blazed grating with azimuthally distributed liquid-crystal directors. Appl Opt 43:5193–5197CrossRefGoogle Scholar
  16. Honma M, Nose T (2012a) Temperature-independent achromatic liquid-crystal grating with spatially distributed twisted-nematic orientation. Appl Phys Express 5:062501CrossRefGoogle Scholar
  17. Honma M, Nose T (2012b) Highly efficient twisted nematic liquid crystal polarization gratings achieved by microrubbing. Appl Phys Lett 101:041107CrossRefGoogle Scholar
  18. Honma M, Nose T (2012c) Twisted nematic liquid crystal polarization grating with the handedness conservation of a circularly polarized state. Opt Express 20:18449–18458CrossRefGoogle Scholar
  19. Hu W, Srivastava AK, Lin XW, Liang X, Wu ZJ, Sun JT, Zhu G, Chigrinov V, Lu YQ (2012) Polarization independent liquid crystal gratings based on orthogonal photoalignments. Appl Phys Lett 100:111116CrossRefGoogle Scholar
  20. Ichimura K (2000) Photoalignment of liquid crystal systems. Chem Rev 100:1847–1873CrossRefGoogle Scholar
  21. Ichimura K, Suzuki Y, Seki T, Hosaki A, Aoki K (1988) Reversible change in alignment mode of nematic liquid crystals regulated photochemically by “command surfaces” modified with an azobenzene monolayer. Langmuir 4:1216–1219CrossRefGoogle Scholar
  22. Ichimura K, Akita Y, Akiyama H, Kudo K, Hayashi Y (1997) Photoreactivity of polymers with regioisomeric cinnamate side chains and their ability to regulate liquid crystal alignment. Macromolecules 30:903–911CrossRefGoogle Scholar
  23. Kawatsuki N, Ono H, Takatsuka H, Yamamoto T, Sangen O (1997a) Liquid crystal alignment on photoreactive side-chain liquid-crystalline polymer generated by linearly polarized UV light. Macromolecules 30:6680–6682CrossRefGoogle Scholar
  24. Kawatsuki N, Takatsuka H, Yamamoto T, Ono H (1997b) Photoregulated liquid crystal alignment on photoreactive side-chain liquid-crystalline polymer. Jpn J Appl Phys 36:6464–6469CrossRefGoogle Scholar
  25. Kawatsuki N, Suehiro C, Yamamoto T (1998) Photoinduced alignment of photo-cross-linkable side-chain liquid crystalline copolymers comprising cinnamoylethoxybiphenyl and cyanobiphenyl groups. Macromolecules 31:5984–5990CrossRefGoogle Scholar
  26. Kawatsuki N, Yamamoto T, Ono H (1999) Photoinduced alignment control of photoreactive side-chain polymer liquid crystal by linearly polarized ultraviolet light. Appl Phys Lett 74:935–937CrossRefGoogle Scholar
  27. Kawatsuki N, Matsuyoshi K, Hayashi M, Takatsuka H, Yamamoto T (2000) Photoreaction of photo-cross-linkable methacrylate polymer films comprising 2-cinnamoyloxyethoxybiphenyl side group by linearly polarized ultraviolet light and liquid crystal alignment on the resultant films. Chem Mater 12:1549–1555CrossRefGoogle Scholar
  28. Kawatsuki N, Kawakami T, Yamamoto T (2001) A photoinduced birefringent film with a high orientational order obtained from a novel polymer liquid crystal. Adv Mater 13:1337–1339CrossRefGoogle Scholar
  29. Kawatsuki N, Goto K, Kawakami T, Yamamoto T (2002) Reversion of alignment direction in the thermally enhanced photoreorientation of photo-cross-linkable polymer liquid crystal films. Macromolecules 35:706–713CrossRefGoogle Scholar
  30. Kawatsuki N, Kuwabara M, Matsuura Y, Ono H, Emoto A (2004) Control of thermally enhanced photoinduced reorientation direction of photocrosslinkable copolymer liquid crystals and application to polarization gratings using linearly polarized ultraviolet light. Jpn J Appl Phys 43:5447–5450CrossRefGoogle Scholar
  31. Kawatsuki N, Hamano K, Ono H, Sasaki T, Goto K (2007) Molecular-oriented photoalignment layer for liquid crystals. Jpn J Appl Phys 46:339–341CrossRefGoogle Scholar
  32. Kawatsuki N, Nishioka E, Emoto A, Ono H, Kondo M (2012) Blazed surface relief formation in azobenzene-containing polymeric films by asymmetric polarization holography. Appl Phys Express 5:041601CrossRefGoogle Scholar
  33. Kumar GS, Neckers DC (1989) Photochemistry of azobenzene-containing polymers. Chem Rev 89:1915–1925CrossRefGoogle Scholar
  34. Kuzuwata M, Sasaki T, Kawatsuki N, Ono H (2012) Fabrication of twisted nematic structure and vector grating cells by one-step exposure on photocrosslinkable polymer liquid crystals. Opt Lett 37:1115–1117CrossRefGoogle Scholar
  35. Labarthet FL, Buffeteau T, Sourisseau C (1999) Azopolymer holographic diffraction gratings: time dependent analysis of the diffraction efficiency, birefringence, and surface modulation induced by two linearly polarized interfering beams. J Phys Chem B 103:6690–6699CrossRefGoogle Scholar
  36. Natansohn A, Rochon P (2002) Photoinduced motions in azo-containing polymers. Chem Rev 102:4139–4175CrossRefGoogle Scholar
  37. Nikolova L, Ramanujam PS (2009) Polarization holography. Cambridge University Press, CambridgeCrossRefGoogle Scholar
  38. Nikolova L, Todorov T (1984) Diffraction efficiency and selectivity of polarization holographic recording. Opt Acta 31:579–588CrossRefGoogle Scholar
  39. Obi M, Morino S, Ichimura K (1999) Factors affecting photoalignment of liquid crystals induced by polymethacrylates with coumarin side chains. Chem Mater 11:656–664CrossRefGoogle Scholar
  40. Okubo K, Kimura M, Akahane T (2003) Measurement of genuine azimuthal anchoring energy in consideration of liquid crystal molecular adsorption on alignment film. Jpn J Appl Phys 42:6428–6433CrossRefGoogle Scholar
  41. Ono H, Emoto A, Takahashi F, Kawatsuki N, Hasegawa T (2003a) Highly stable polarization gratings in photocrosslinkable polymer liquid crystals. J Appl Phys 94:1298–1303CrossRefGoogle Scholar
  42. Ono H, Emoto A, Kawatsuki N, Hasegawa T (2003b) Multiplex diffraction from functionalized polymer liquid crystals and polarization conversion. Opt Express 11:2379–2384CrossRefGoogle Scholar
  43. Ono H, Emoto A, Kawatsuki N, Uchida E, Kuwabara M (2004) New fabrication method for anisotropic gratings formed in photocrosslinkable polymer liquid crystals. Appl Phys A 79:1725–1727CrossRefGoogle Scholar
  44. Ono H, Oikawa S, Kawatsuki N (2007) Effects of anchoring strength on diffraction properties of liquid crystal phase gratings formed on photoalignment polymer films. J Appl Phys 101:123523CrossRefGoogle Scholar
  45. Ono H, Hishida M, Emoto A, Shioda T, Kawatsuki N (2009) Elastic continuum analysis and diffraction properties of two-dimensional liquid crystalline grating cells. J Opt Soc Am B 26:1151–1156CrossRefGoogle Scholar
  46. Park JH, Yu CJ, Kim J, Chung SY, Lee SD (2003) Concept of a liquid-crystal polarization beamsplitter based on binary phase gratings. Appl Phys Lett 83:1918–1920CrossRefGoogle Scholar
  47. Provenzano C, Pagliusi P, Cipparrone G (2007) Electrically tunable two-dimensional liquid crystal gratings induced by polarization holography. Opt Express 15:5872–5878CrossRefGoogle Scholar
  48. Sasaki T, Ono H, Kawatsuki N, Kuwabara M (2005) Liquid crystal phase gratings using photoregulated photocrosslinkable polymer liquid crystals. Appl Phys Lett 87:161112CrossRefGoogle Scholar
  49. Sasaki T, Hatayama A, Emoto A, Ono H, Kawatsuki N (2006) Simple detection of light polarization by using crossed polarization gratings. J Appl Phys 100:063502CrossRefGoogle Scholar
  50. Sasaki T, Ono H, Kawatsuki N, Kuwabara M (2007) Diffraction properties of nematic phase gratings with photoregulated liquid crystal cells. Jpn J Appl Phys 46:698–702CrossRefGoogle Scholar
  51. Sasaki T, Kuzuwata M, Noda K, Kawatsuki N, Ono H (2013) Liquid Crystal gratings with twisted alignment produced by one-step polarizer-rotation exposure on photocrosslinkable polymer liquid crystal films. Jpn J Appl Phys 52:042503CrossRefGoogle Scholar
  52. Sasaki T, Wada T, Noda K, Kawatsuki N, Ono H (2014) Merged vector gratings recorded in a photocrosslinkable polymer liquid crystal film for polarimetry. J Appl Phys 115:023110CrossRefGoogle Scholar
  53. Sato S (1979) Liquid-crystal lens-cells with variable focal length. Jpn J Appl Phys 18:1679–1684CrossRefGoogle Scholar
  54. Scharf T (2007) Polarized light in liquid crystals and polymers. Wiley, New JerseyGoogle Scholar
  55. Seki T, Nagano S, Hara M (2013) Versatility of photoalignment techniques: from nematics to a wide range of functional materials. Polymer 54:6053–6072CrossRefGoogle Scholar
  56. Schadt M, Schmitt K, Kozinkov V, Chigrinov V (1992) Surface-induced parallel alignment of liquid crystals by linearly polarized photopolymers. Jpn J Appl Phys 31:2155–2164CrossRefGoogle Scholar
  57. Stallinga S (1999) Berreman 4 × 4 matrix method for reflective liquid crystal displays. J Appl Phys 85:3023–3031CrossRefGoogle Scholar
  58. Subacius P, Bos PJ, Lavrentovich OD (1997a) Switchable diffractive cholesteric gratings. Appl Phys Lett 71:1350–1352CrossRefGoogle Scholar
  59. Subacius P, Shiyanovskii SV, Bos PJ, Lavrentovich OD (1997b) Cholesteric gratings with field-controlled period. Appl Phys Lett 71:3323–3325CrossRefGoogle Scholar
  60. Sun J, Srivastava AK, Wang L, Chigrinov VG, Kwok HS (2013) Optically tunable and rewritable diffraction grating with photoaligned liquid crystals. Opt Lett 38:2342–2344CrossRefGoogle Scholar
  61. Todorov T, Nikolova L, Stoyanova K, Tomova N (1985) Polarization holograph. 3: some applications of polarization holographic recording. Appl Opt 24:785–788CrossRefGoogle Scholar
  62. Wu WY, Mo TS, Fuh AYG (2006) Polarization characteristics of diffracted beams from twisted nematic gratings fabricated by the photoalignment effect in dye-doped liquid crystal films. J Opt Soc Am B 23:1737–1742CrossRefGoogle Scholar
  63. Yadavalli NS, Santer S (2013) In-situ atomic force microscopy study of the mechanism of surface relief grating formation in photosensitive polymer films. J Phys Chem B 115:1363–1367Google Scholar
  64. Yeh P, Gu G (1999) Optics of liquid crystal displays. Wiley, New YorkGoogle Scholar
  65. Yu CJ, Kim DW, Kim J, Lee SD (2005) Polarization-invariant grating based on a photoaligned liquid crystal in an oppositely twisted binary configuration. Opt Lett 30:1995–1997CrossRefGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Tomoyuki Sasaki
    • 1
  • Kohei Noda
    • 1
  • Hiroshi Ono
    • 1
  • Nobuhiro Kawatsuki
    • 2
  1. 1.Department of Electrical EngineeringNagaoka University of TechnologyNagaokaJapan
  2. 2.Department of Applied Chemistry, Graduate School of EngineeringUniversity of HyogoHimejiJapan

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