Abstract

This investigation demonstrates a simple but accurate method for measuring the helical twisting power of chiral doped liquid crystals using axially symmetrical photo-alignment in azo dye-doped liquid crystal films. As reported in our previous paper, a reversed twist effect produces a disclination line in photo-aligned axially symmetrical liquid crystal films. The pitch and helical twisting power can be obtained by measuring the rotation angle of the disclination line in chrial doped liquid crystal. This method is independent of cell gap and provide an error below 0.5%.

© 2009 OSA

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  1. M.-D. Tillin, “Voltage reduction in twisted nematic liquid crystals by reverse (negative) doping,” J. Appl. Phys. 102(7), 073101 (2007).
    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef]
  15. D. Voloshchenko, A. Khyzhnyak, Y. Reznikov, and V. Reshetnyak, “Control of an easy-axis on nematicpolymer interface by light action to nematic bulk,” Jpn. J. Appl. Phys. 34(Part 1, No. 2A), 566–571 (1995).
    [CrossRef]

2009

T. Sasaki, A. Emoto, T. Shioda, and H. Ono, “Transmission and reflection phase gratings formed in azo-dye-doped chiral nematic liquid crystals,” Appl. Phys. Lett. 94(2), 023303 (2009).
[CrossRef]

2008

2007

S.-S. Choi, S.-M. Morris, H.-J. Coles, and W. T. S. Huck, “Wavelength tuning the photonic band gap in chiral nematic liquid crystals using electrically commanded surfaces,” Appl. Phys. Lett. 91(23), 231110 (2007).
[CrossRef]

M.-D. Tillin, “Voltage reduction in twisted nematic liquid crystals by reverse (negative) doping,” J. Appl. Phys. 102(7), 073101 (2007).
[CrossRef]

2006

J.-F. Strömer, D. Marenduzzo, C.-V. Brown, J.-M. Yeomans, and E.-P. Raynes, “Electric-field-induced disclination migration in a Grandjean-Cano wedge,” J. Appl. Phys. 99(6), 064911 (2006).
[CrossRef]

2005

T.-H. Lin, Y.-J. Chen, C.-H. Wu, A. Y.-G. Fuh, J.-H. Liu, and P.-C. Yang, “Cholesteric liquid crystal laser with wide tuning capability,” Appl. Phys. Lett. 86(16), 161120 (2005).
[CrossRef]

2001

1998

H. Bock, “Random domain formation in 0°–360° bistable nematic twist cells,” Appl. Phys. Lett. 73(20), 2905 (1998).
[CrossRef]

F. Vicentini and L.-C. Chien, “Tunable chiral materials for multicolor reflective cholesteric displays,” Liq. Cryst. 24(4), 483–488 (1998).
[CrossRef]

1995

D. Voloshchenko, A. Khyzhnyak, Y. Reznikov, and V. Reshetnyak, “Control of an easy-axis on nematicpolymer interface by light action to nematic bulk,” Jpn. J. Appl. Phys. 34(Part 1, No. 2A), 566–571 (1995).
[CrossRef]

1994

D.-K. Yang, J.-W. Doane, Z. Yaniv, and J. Glasser, “Cholesteric reflective display: drive scheme and contrast,” Appl. Phys. Lett. 64(15), 1905 (1994).
[CrossRef]

Bock, H.

H. Bock, “Random domain formation in 0°–360° bistable nematic twist cells,” Appl. Phys. Lett. 73(20), 2905 (1998).
[CrossRef]

Brown, C.-V.

J.-F. Strömer, D. Marenduzzo, C.-V. Brown, J.-M. Yeomans, and E.-P. Raynes, “Electric-field-induced disclination migration in a Grandjean-Cano wedge,” J. Appl. Phys. 99(6), 064911 (2006).
[CrossRef]

Chen, Y.-J.

T.-H. Lin, Y.-J. Chen, C.-H. Wu, A. Y.-G. Fuh, J.-H. Liu, and P.-C. Yang, “Cholesteric liquid crystal laser with wide tuning capability,” Appl. Phys. Lett. 86(16), 161120 (2005).
[CrossRef]

Chien, L.-C.

F. Vicentini and L.-C. Chien, “Tunable chiral materials for multicolor reflective cholesteric displays,” Liq. Cryst. 24(4), 483–488 (1998).
[CrossRef]

Choi, S.-S.

S.-S. Choi, S.-M. Morris, H.-J. Coles, and W. T. S. Huck, “Wavelength tuning the photonic band gap in chiral nematic liquid crystals using electrically commanded surfaces,” Appl. Phys. Lett. 91(23), 231110 (2007).
[CrossRef]

Coles, H.-J.

S.-S. Choi, S.-M. Morris, H.-J. Coles, and W. T. S. Huck, “Wavelength tuning the photonic band gap in chiral nematic liquid crystals using electrically commanded surfaces,” Appl. Phys. Lett. 91(23), 231110 (2007).
[CrossRef]

Doane, J.-W.

D.-K. Yang, J.-W. Doane, Z. Yaniv, and J. Glasser, “Cholesteric reflective display: drive scheme and contrast,” Appl. Phys. Lett. 64(15), 1905 (1994).
[CrossRef]

Emoto, A.

T. Sasaki, A. Emoto, T. Shioda, and H. Ono, “Transmission and reflection phase gratings formed in azo-dye-doped chiral nematic liquid crystals,” Appl. Phys. Lett. 94(2), 023303 (2009).
[CrossRef]

Fuh, A. Y.

Fuh, A. Y.-G.

T.-H. Lin, Y.-J. Chen, C.-H. Wu, A. Y.-G. Fuh, J.-H. Liu, and P.-C. Yang, “Cholesteric liquid crystal laser with wide tuning capability,” Appl. Phys. Lett. 86(16), 161120 (2005).
[CrossRef]

A. Y.-G. Fuh, C.-C. Liao, K.-C. Hsu, C.-L. Lu, and C.-Y. Tsai, “Dynamic studies of holographic gratings in dye-doped liquid-crystal films,” Opt. Lett. 26(22), 1767–1769 (2001).
[CrossRef]

Glasser, J.

D.-K. Yang, J.-W. Doane, Z. Yaniv, and J. Glasser, “Cholesteric reflective display: drive scheme and contrast,” Appl. Phys. Lett. 64(15), 1905 (1994).
[CrossRef]

Hsu, K.-C.

Huck, W. T. S.

S.-S. Choi, S.-M. Morris, H.-J. Coles, and W. T. S. Huck, “Wavelength tuning the photonic band gap in chiral nematic liquid crystals using electrically commanded surfaces,” Appl. Phys. Lett. 91(23), 231110 (2007).
[CrossRef]

Ke, S.-W.

Khyzhnyak, A.

D. Voloshchenko, A. Khyzhnyak, Y. Reznikov, and V. Reshetnyak, “Control of an easy-axis on nematicpolymer interface by light action to nematic bulk,” Jpn. J. Appl. Phys. 34(Part 1, No. 2A), 566–571 (1995).
[CrossRef]

Ko, S. W.

Liao, C.-C.

Lin, T.-H.

Liu, J.-H.

T.-H. Lin, Y.-J. Chen, C.-H. Wu, A. Y.-G. Fuh, J.-H. Liu, and P.-C. Yang, “Cholesteric liquid crystal laser with wide tuning capability,” Appl. Phys. Lett. 86(16), 161120 (2005).
[CrossRef]

Lu, C.-L.

Marenduzzo, D.

J.-F. Strömer, D. Marenduzzo, C.-V. Brown, J.-M. Yeomans, and E.-P. Raynes, “Electric-field-induced disclination migration in a Grandjean-Cano wedge,” J. Appl. Phys. 99(6), 064911 (2006).
[CrossRef]

Morris, S.-M.

S.-S. Choi, S.-M. Morris, H.-J. Coles, and W. T. S. Huck, “Wavelength tuning the photonic band gap in chiral nematic liquid crystals using electrically commanded surfaces,” Appl. Phys. Lett. 91(23), 231110 (2007).
[CrossRef]

Ono, H.

T. Sasaki, A. Emoto, T. Shioda, and H. Ono, “Transmission and reflection phase gratings formed in azo-dye-doped chiral nematic liquid crystals,” Appl. Phys. Lett. 94(2), 023303 (2009).
[CrossRef]

Raynes, E.-P.

J.-F. Strömer, D. Marenduzzo, C.-V. Brown, J.-M. Yeomans, and E.-P. Raynes, “Electric-field-induced disclination migration in a Grandjean-Cano wedge,” J. Appl. Phys. 99(6), 064911 (2006).
[CrossRef]

Reshetnyak, V.

D. Voloshchenko, A. Khyzhnyak, Y. Reznikov, and V. Reshetnyak, “Control of an easy-axis on nematicpolymer interface by light action to nematic bulk,” Jpn. J. Appl. Phys. 34(Part 1, No. 2A), 566–571 (1995).
[CrossRef]

Reznikov, Y.

D. Voloshchenko, A. Khyzhnyak, Y. Reznikov, and V. Reshetnyak, “Control of an easy-axis on nematicpolymer interface by light action to nematic bulk,” Jpn. J. Appl. Phys. 34(Part 1, No. 2A), 566–571 (1995).
[CrossRef]

Sasaki, T.

T. Sasaki, A. Emoto, T. Shioda, and H. Ono, “Transmission and reflection phase gratings formed in azo-dye-doped chiral nematic liquid crystals,” Appl. Phys. Lett. 94(2), 023303 (2009).
[CrossRef]

Shioda, T.

T. Sasaki, A. Emoto, T. Shioda, and H. Ono, “Transmission and reflection phase gratings formed in azo-dye-doped chiral nematic liquid crystals,” Appl. Phys. Lett. 94(2), 023303 (2009).
[CrossRef]

Strömer, J.-F.

J.-F. Strömer, D. Marenduzzo, C.-V. Brown, J.-M. Yeomans, and E.-P. Raynes, “Electric-field-induced disclination migration in a Grandjean-Cano wedge,” J. Appl. Phys. 99(6), 064911 (2006).
[CrossRef]

Tillin, M.-D.

M.-D. Tillin, “Voltage reduction in twisted nematic liquid crystals by reverse (negative) doping,” J. Appl. Phys. 102(7), 073101 (2007).
[CrossRef]

Ting, C.-L.

Tsai, C.-Y.

Tzeng, Y.-Y.

Vicentini, F.

F. Vicentini and L.-C. Chien, “Tunable chiral materials for multicolor reflective cholesteric displays,” Liq. Cryst. 24(4), 483–488 (1998).
[CrossRef]

Voloshchenko, D.

D. Voloshchenko, A. Khyzhnyak, Y. Reznikov, and V. Reshetnyak, “Control of an easy-axis on nematicpolymer interface by light action to nematic bulk,” Jpn. J. Appl. Phys. 34(Part 1, No. 2A), 566–571 (1995).
[CrossRef]

Wang, C.-T.

Wu, C.-H.

T.-H. Lin, Y.-J. Chen, C.-H. Wu, A. Y.-G. Fuh, J.-H. Liu, and P.-C. Yang, “Cholesteric liquid crystal laser with wide tuning capability,” Appl. Phys. Lett. 86(16), 161120 (2005).
[CrossRef]

Yang, D.-K.

D.-K. Yang, J.-W. Doane, Z. Yaniv, and J. Glasser, “Cholesteric reflective display: drive scheme and contrast,” Appl. Phys. Lett. 64(15), 1905 (1994).
[CrossRef]

Yang, P.-C.

T.-H. Lin, Y.-J. Chen, C.-H. Wu, A. Y.-G. Fuh, J.-H. Liu, and P.-C. Yang, “Cholesteric liquid crystal laser with wide tuning capability,” Appl. Phys. Lett. 86(16), 161120 (2005).
[CrossRef]

Yaniv, Z.

D.-K. Yang, J.-W. Doane, Z. Yaniv, and J. Glasser, “Cholesteric reflective display: drive scheme and contrast,” Appl. Phys. Lett. 64(15), 1905 (1994).
[CrossRef]

Yeomans, J.-M.

J.-F. Strömer, D. Marenduzzo, C.-V. Brown, J.-M. Yeomans, and E.-P. Raynes, “Electric-field-induced disclination migration in a Grandjean-Cano wedge,” J. Appl. Phys. 99(6), 064911 (2006).
[CrossRef]

Appl. Phys. Lett.

H. Bock, “Random domain formation in 0°–360° bistable nematic twist cells,” Appl. Phys. Lett. 73(20), 2905 (1998).
[CrossRef]

T. Sasaki, A. Emoto, T. Shioda, and H. Ono, “Transmission and reflection phase gratings formed in azo-dye-doped chiral nematic liquid crystals,” Appl. Phys. Lett. 94(2), 023303 (2009).
[CrossRef]

S.-S. Choi, S.-M. Morris, H.-J. Coles, and W. T. S. Huck, “Wavelength tuning the photonic band gap in chiral nematic liquid crystals using electrically commanded surfaces,” Appl. Phys. Lett. 91(23), 231110 (2007).
[CrossRef]

T.-H. Lin, Y.-J. Chen, C.-H. Wu, A. Y.-G. Fuh, J.-H. Liu, and P.-C. Yang, “Cholesteric liquid crystal laser with wide tuning capability,” Appl. Phys. Lett. 86(16), 161120 (2005).
[CrossRef]

D.-K. Yang, J.-W. Doane, Z. Yaniv, and J. Glasser, “Cholesteric reflective display: drive scheme and contrast,” Appl. Phys. Lett. 64(15), 1905 (1994).
[CrossRef]

J. Appl. Phys.

M.-D. Tillin, “Voltage reduction in twisted nematic liquid crystals by reverse (negative) doping,” J. Appl. Phys. 102(7), 073101 (2007).
[CrossRef]

J.-F. Strömer, D. Marenduzzo, C.-V. Brown, J.-M. Yeomans, and E.-P. Raynes, “Electric-field-induced disclination migration in a Grandjean-Cano wedge,” J. Appl. Phys. 99(6), 064911 (2006).
[CrossRef]

Jpn. J. Appl. Phys.

D. Voloshchenko, A. Khyzhnyak, Y. Reznikov, and V. Reshetnyak, “Control of an easy-axis on nematicpolymer interface by light action to nematic bulk,” Jpn. J. Appl. Phys. 34(Part 1, No. 2A), 566–571 (1995).
[CrossRef]

Liq. Cryst.

F. Vicentini and L.-C. Chien, “Tunable chiral materials for multicolor reflective cholesteric displays,” Liq. Cryst. 24(4), 483–488 (1998).
[CrossRef]

Opt. Express

Opt. Lett.

Other

S.-T. Wu, and D.-K. Yang, Reflective Liquid Crystal Displays, (2001), p.197.

P. Oswald, and P. Pieranski, Nematic and Cholesteric Liquid Crystals, (2005), p.446.

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Figures (6)

Fig. 1
Fig. 1

Fabrication setup.

Fig. 2
Fig. 2

(a) Alignment of homogeneous-radial sample ; (b) and (c) LC molecular structure in homogeneous-radial sample with and without chiral dopant, respectively.

Fig. 3
Fig. 3

Images of homogeneous-radial LC film with various chiral dopant concentrations of CB15 under crossed-polarized optical microscope (POM); (a) 0.101 wt%, (b) 0.175 wt%, (c) 0.247 wt%, (d) 0.291 wt%. Yellow rectangles and black dotted lines are the marks of disclination lines in chiral-doped and -undoped LC films, respectively. R: rubbing direction. P: polarizer, A: analyzer.

Fig. 4
Fig. 4

Images of homogeneous-radial LC film with chiral dopant concentrations of S811; (a) 0.042 wt%, (b) 0.085wt%, (c) 0.126 wt%, (d) 0.190 wt%. Yellow rectangles and black dotted lines are the marks of disclination line in chiral-doped and -undoped DDLC films, respectively. R: rubbing direction. P: polarizer, A: analyzer.

Fig. 5
Fig. 5

Variation of angle of rotation ϕ of disclination line with chiral concentrations.

Fig. 6
Fig. 6

H.T.P. of chiral dopants CB15 and S811.

Tables (1)

Tables Icon

Table 1 H.T.P. of CB15 measured by different measuring methods.

Equations (2)

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p=2πdφ
H.T.P.=1pc=φ2πcd

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