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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 18, Iss. 19 — Sep. 13, 2010
  • pp: 19914–19919

Voltage-assisted photoaligning effect of an azo dye doped in a liquid crystal with negative dielectric anisotropy

Kuang-Yu Yang and Wei Lee  »View Author Affiliations

Optics Express, Vol. 18, Issue 19, pp. 19914-19919 (2010)

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We demonstrate a method of controlling the pretilt angle by field-assisted photoalignment in a vertically-aligned liquid crystal doped with a dichroic azo dye. By dynamically measuring both the pretilt angle and anisotropy in absorbance, we present detailed alignment variations in both the polar and azimuthal directions with the time of laser exposure that induces photoisomerization of the dye molecules. Significant differences in the resulting pretilt as well as optically-absorptive anisotropy are manifested between a regular photoalignment procedure and that in conjunction with a bias voltage during irradiation. It is found that the field-assisted exposure not only speeds up the photoalignment along the polarization direction of the laser beam but also leads to a higher orientational order.

© 2010 OSA

OCIS Codes
(160.3710) Materials : Liquid crystals
(230.3720) Optical devices : Liquid-crystal devices
(300.1030) Spectroscopy : Absorption

ToC Category:
Optical Devices

Original Manuscript: June 8, 2010
Revised Manuscript: July 22, 2010
Manuscript Accepted: August 7, 2010
Published: September 3, 2010

Kuang-Yu Yang and Wei Lee, "Voltage-assisted photoaligning effect of an azo dye doped in a liquid crystal with negative dielectric anisotropy," Opt. Express 18, 19914-19919 (2010)

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  1. V. G. Chigrinov, V. M. Kozenkov, and H. S. Kwok, Photoalignment of Liquid Crystalline Materials: Physics and Applications (Wiley, 2008).
  2. T.-J. Chen and K.-L. Chu, “Pretilt angle control for single-cell-gap transflective liquid crystal cells,” Appl. Phys. Lett. 92(9), 091102 (2008). [CrossRef]
  3. L. Komitov, C. Ruslim, Y. Matsuzawa, and K. Ichimura, “Photoinduced anchoring transitions in a nematic doped with azo dyes,” Liq. Cryst. 27(8), 1011–1016 (2000). [CrossRef]
  4. W. M. Gibbons, P. J. Shannon, S.-T. Sun, and B. J. Swetlin, “Surface-mediated alignment of nematic liquid crystals with polarized laser light,” Nature 351(6321), 49–50 (1991). [CrossRef]
  5. E. Ouskova, D. Fedorenko, Yu. Reznikov, S. V. Shiyanovskii, L. Su, J. L. West, O. V. Kuksenok, O. Francescangeli, and F. Simoni, “Hidden photoalignment of liquid crystals in the isotropic phase,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 63(2 Pt 1), 021701 (2001). [CrossRef] [PubMed]
  6. A. Y.-G. Fuh, C.-C. Liao, K.-C. Hsu, and C.-L. Lu, “Laser-induced reorientation effect and ripple structure in dye-doped liquid-crystal films,” Opt. Lett. 28(14), 1179–1181 (2003). [CrossRef] [PubMed]
  7. A. Y.-G. Fuh, C.-K. Liu, K.-T. Cheng, C.-L. Ting, C.-C. Chen, P. C.-P. Chao, and H.-K. Hsu, “Chao, and H.-K. Hsu, “Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals,” Appl. Phys. Lett. 95(16), 161104 (2009). [CrossRef]
  8. F. J. Kahn, G. N. Taylor, and H. Schonhorn, “Surface-produced alignment of liquid crystals,” Proc. IEEE 61(7), 823–828 (1973). [CrossRef]
  9. J. S. Gwag, S. H. Lee, K.-H. Park, W. S. Park, K.-Y. Han, C. G. Jhun, T.-H. Yoon, J. C. Kim, D.- Song, and D.- Shin, “Simple method for measuring the high pretilt angle of nematic liquid crystals,” J. Appl. Phys. 93(8), 4936 (2003). [CrossRef]
  10. C.-Y. Tang, S.-M. Huang, and W. Lee, “Dielectric relaxation dynamics in a dual-frequency nematic liquid crystal doped with C.I. Acid Red 2,” Dyes Pigm. in press., doi:.
  11. D. W. Berreman, “Solid surface shape and the alignment of an adjacent nematic liquid crystal,” Phys. Rev. Lett. 28(26), 1683–1686 (1972). [CrossRef]
  12. J. Fukuda, M. Yoneya, and H. Yokoyama, “Consistent numerical evaluation of the anchoring energy of a grooved surface,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 79(1 Pt 1), 011705 (2009). [CrossRef] [PubMed]

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