Abstract

The reflection and transmission properties of photosensitized cholesteric liquid crystals (CLCs) are examined. Introduction of mesogenic push-pull azobenzene dyes into blue and green reflective CLCs enables fast (sub-second), photoswitchable optical properties due to the overlap of the trans and cis absorption states. Upon irradiation with CW blue-green laser radiation, the bandgap reflection is erased in a fraction of a second and reversibly restored approximately one second after the blue-green laser radiation is removed. Given the strong overlap of the trans and cis absorption maxima, we believe that repeated trans-cis and cis-trans isomerization cycles induced with irradiation lead to a destruction of the ordered LC phase. The sensitivity to the irradiating wavelength scales with the wavelength-dependent absorption of the mesogenic push-pull dye. A detailed examination of the transmitted and reflected laser beams are presented as a function of power and wavelength of CW sources.

© 2011 OSA

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References

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  1. P. G. de Gennes, The Physics of Liquid Crystals (Clarendon, Cambridge, 1977)
  2. D. M. Makow and C. L. Sanders, “Additive colour properties and colour gamut of cholesteric liquid crystals,” Nature276(5683), 48–50 (1978).
    [CrossRef]
  3. S.-T. Wu and D.-K. Yang, Reflective Liquid Crystal Displays (Wiley, 2001).
  4. A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, and M. P. De Santo, “Cholesteric liquid crystal mixtures sensitive to different ranges of solar UV irradiation,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)434(1), 25/[353]–38/[366] (2005).
    [CrossRef]
  5. F. Simoni, G. Cipparrone, and R. Bartolino, “Tuning of a dye laser by a liquid crystal,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)139(1–2), 161–169 (1986).
    [CrossRef]
  6. G. S. Chilaya, “Light-controlled change in the helical pitch and broadband tunable cholesteric liquid-crystal lasers,” Crystallogr. Rep.51(S1), S108–S118 (2006).
    [CrossRef]
  7. A. Y. G. Fuh, T.-H. Lin, J. H. Liu, and F. C. Wu, “Lasing in chiral photonic liquid crystals and associated frequency tuning,” Opt. Express12(9), 1857–1863 (2004).
    [CrossRef] [PubMed]
  8. S. Furumi, S. Yokoyama, A. Otomo, and S. Mashiko, “Phototunable photonic bandgap in a chiral liquid crystal laser device,” Appl. Phys. Lett.84(14), 2491–2493 (2004).
    [CrossRef]
  9. T. J. White, M. E. McConney, and T. J. Bunning, “Dynamic color in stimuli-responsive cholesteric liquid crystals,” J. Mater. Chem.20(44), 9832–9847 (2010).
    [CrossRef]
  10. F. Ania and H. Stegemeyer, “Cholesteric pitch behavior at the phase transition cholesteric to smectic B,” Mol. Cryst. Liq. Cryst. Lett.2(3–4), 67–76 (1985).
  11. R. S. Pindak, C.-C. Huang, and J. T. Ho, “Divergence of cholesteric pitch near a smectic A transition,” Phys. Rev. Lett.32(2), 43–46 (1974).
    [CrossRef]
  12. F. Zhang and D. K. Yang, “Temperature dependence of pitch and twist elastic constant in a cholesteric to smectic A phase transition,” Liq. Cryst.29(12), 1497–1501 (2002).
    [CrossRef]
  13. M. E. McConney, V. P. Tondiglia, J. M. Hurtubise, L. V. Natarajan, T. J. White, and T. J. Bunning, “Thermally induced, multicolored hyper-reflective cholesteric liquid crystals,” Adv. Mater. (Deerfield Beach Fla.)23(12), 1453–1457 (2011).
    [CrossRef] [PubMed]
  14. E. Sackmann, “Photochemically induced reversible color changes in cholesteric liquid crystals,” J. Am. Chem. Soc.93(25), 7088–7090 (1971).
    [CrossRef]
  15. W. Haas, J. Adams, and J. Wysocki, “Interaction between uv radiation and cholesteric liquid crystals,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)7(1), 371–379 (1969).
    [CrossRef]
  16. J. Adams and W. Haas, “Sensitivity of cholesteric films to ultraviolet exposure,” J. Electrochem. Soc.118(12), 2026–2028 (1971).
    [CrossRef]
  17. V. Vinvogradov, A. Khizhnyak, L. Kutulya, Y. Reznikov, and V. Resihetnyak, “Photoinduced change of cholesteric LC-pitch,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)192(1), 273–278 (1990).
    [CrossRef]
  18. M. Z. Alam, T. Yoshioka, T. Ogata, T. Nonaka, and S. Kurihara, “Influence of helical twisting power on the photoswitching behavior of chiral azobenzene compounds: applications to high-performance switching devices,” Chemistry13(9), 2641–2647 (2007).
    [CrossRef] [PubMed]
  19. R. Eelkema and B. L. Feringa, “Reversible full-range color control of a cholesteric liquid-crystalline film by using a molecular motor,” Chem. Asian J.1(3), 367–369 (2006).
    [CrossRef] [PubMed]
  20. A. Chanishvili, G. Chilaya, G. Petriashvili, and D. Sikharulidze, “Light induced effects in cholesteric mixtures with a photosensitive nematic host,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)409, 209–218 (2004).
    [CrossRef]
  21. S. Kurihara, S. Nomiyama, and T. Nonaka, “Photochemical switching between a compensated nematic phase and a twisted nematic phase by photoisomerization of chiral azobenzene molecules,” Chem. Mater.12(1), 9–12 (2000).
    [CrossRef]
  22. S. S. Choi, S. M. Morris, W. T. S. Huck, and H. J. Coles, “Simultaneous red-green-blue reflection and wavelength tuning from an achiral liquid crystal and a polymer template,” Adv. Mater. (Deerfield Beach Fla.)22(1), 53–56 (2010).
    [CrossRef] [PubMed]
  23. M. Xu and D.-K. Yang, “Dual frequency cholesteric light shutters,” Appl. Phys. Lett.70(6), 720–722 (1997).
    [CrossRef]
  24. C. A. Bailey, V. P. Tondiglia, L. V. Natarajan, M. M. Duning, R. L. Bricker, R. L. Sutherland, T. J. White, M. F. Durstock, and T. J. Bunning, “Electromechanical tuning of cholesteric liquid crystals,” J. Appl. Phys.107(1), 013105 (2010).
    [CrossRef]
  25. N. Tamaoki and T. Kamei, “Reversible photo-regulation of the properties of liquid crystals doped with photochromic compounds,” J. Photochem. Photobiol. Chem.11(2–3), 47–61 (2010).
  26. K. G. Yager and C. J. Barrett, “Novel photo-switching using azobenzene functional materials,” J. Photochem. Photobiol. A182(3), 250–261 (2006).
    [CrossRef]
  27. O. Tsutsumi, A. Kanazawa, T. Shiono, T. Ikeda, and L.-S. Park, “Photoinduced phase transition of nematic liquid crystals with donor-acceptor azobenzenes: mechanism of the thermal recovery of the nematic phase,” Phys. Chem. Chem. Phys.1(18), 4219–4224 (1999).
    [CrossRef]
  28. U. A. Hrozhyk, S. V. Serak, N. V. Tabiryan, L. Hoke, D. M. Steeves, B. Kimball, and G. Kedziora,”Systematic study of absorption spectra of donor–acceptor azobenzene mesogenic structures,” Mol. Cryst. Liq. Cryst. 489, 257[583]–272[598] (2008).
  29. U. A. Hrozhyk, S. V. Serak, N. V. Tabiryan, L. Hoke, D. M. Steeves, and B. R. Kimball, “Azobenzene liquid crystalline materials for efficient optical switching with pulsed and/or continuous wave laser beams,” Opt. Express18(8), 8697–8704 (2010).
    [CrossRef] [PubMed]
  30. U. Hrozhyk, S. Serak, N. Tabiryan, D. Steeves, L. Hoke, and B. Kimball, “Azobenzene liquid crystals for fast reversible optical switching and enhanced sensitivity for visible wavelengths,” Proc. SPIE7414, 74140L, (2009).
    [CrossRef]
  31. L. De Sio, S. Serak, N. Tabiryan, and C. Umeton, “Mesogenic versus non-mesogenic azo dye confined in a soft-matter template for realization of optically switchable diffraction gratings,” J. Mater. Chem.21(19), 6811–6814 (2011).
    [CrossRef]
  32. U. A. Hrozhyk, S. V. Serak, N. V. Tabiryan, T. J. White, and T. J. Bunning, “Optically switchable, rapidly relaxing cholesteric liquid crystal reflectors,” Opt. Express18(9), 9651–9657 (2010).
    [CrossRef] [PubMed]
  33. U. Hrozhyk, S. Serak, N. Tabiryan, and T. J. Bunning, “Wide temperature range azobenzene nematic and smectic LC materials,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)454(1), 235/[637]–245/[647] (2006).
    [CrossRef]
  34. N. V. Tabiryan, S. V. Serak, and V. A. Grozhik, “Photoinduced critical opalescence and reversible all-optical switching in photosensitive liquid crystals,” J. Opt. Soc. Am. B20(3), 538–544 (2003).
    [CrossRef]
  35. U. A. Hrozhyk, S. V. Serak, N. V. Tabiryan, and T. J. Bunning, “Optical Tuning of the Reflection of Cholesterics Doped with Azobenzene Liquid Crystals,” Adv. Funct. Mater.17(11), 1735–1742 (2007).
    [CrossRef]
  36. S. Serak, N. Tabiryan, and T. Bunning, “Nonlinear transmission of photosensitive cholesteric liquid crystals due to spectral bandwidth auto-tuning or restoration,” J. Nonlinear Opt. Phys. Mater.16(04), 471–483 (2007).
    [CrossRef]
  37. U. Hrozhyk, S. Serak, N. Tabiryan, L. Hoke, D. M. Steeves, G. Kedziora, and B. Kimball, “High optical nonlinearity of azobenzene liquid crystals for short laser pulses,” Proc. SPIE7050, 705007 (2008).
  38. S. Serak and N. Tabiryan, “Microwatt power optically controlled spatial solitons in azobenzene liquid crystals,” Proc. SPIE6332, 63320Y1–63320Y13 (2006).

Other

P. G. de Gennes, The Physics of Liquid Crystals (Clarendon, Cambridge, 1977)

D. M. Makow and C. L. Sanders, “Additive colour properties and colour gamut of cholesteric liquid crystals,” Nature276(5683), 48–50 (1978).
[CrossRef]

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

A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, and M. P. De Santo, “Cholesteric liquid crystal mixtures sensitive to different ranges of solar UV irradiation,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)434(1), 25/[353]–38/[366] (2005).
[CrossRef]

F. Simoni, G. Cipparrone, and R. Bartolino, “Tuning of a dye laser by a liquid crystal,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)139(1–2), 161–169 (1986).
[CrossRef]

G. S. Chilaya, “Light-controlled change in the helical pitch and broadband tunable cholesteric liquid-crystal lasers,” Crystallogr. Rep.51(S1), S108–S118 (2006).
[CrossRef]

A. Y. G. Fuh, T.-H. Lin, J. H. Liu, and F. C. Wu, “Lasing in chiral photonic liquid crystals and associated frequency tuning,” Opt. Express12(9), 1857–1863 (2004).
[CrossRef] [PubMed]

S. Furumi, S. Yokoyama, A. Otomo, and S. Mashiko, “Phototunable photonic bandgap in a chiral liquid crystal laser device,” Appl. Phys. Lett.84(14), 2491–2493 (2004).
[CrossRef]

T. J. White, M. E. McConney, and T. J. Bunning, “Dynamic color in stimuli-responsive cholesteric liquid crystals,” J. Mater. Chem.20(44), 9832–9847 (2010).
[CrossRef]

F. Ania and H. Stegemeyer, “Cholesteric pitch behavior at the phase transition cholesteric to smectic B,” Mol. Cryst. Liq. Cryst. Lett.2(3–4), 67–76 (1985).

R. S. Pindak, C.-C. Huang, and J. T. Ho, “Divergence of cholesteric pitch near a smectic A transition,” Phys. Rev. Lett.32(2), 43–46 (1974).
[CrossRef]

F. Zhang and D. K. Yang, “Temperature dependence of pitch and twist elastic constant in a cholesteric to smectic A phase transition,” Liq. Cryst.29(12), 1497–1501 (2002).
[CrossRef]

M. E. McConney, V. P. Tondiglia, J. M. Hurtubise, L. V. Natarajan, T. J. White, and T. J. Bunning, “Thermally induced, multicolored hyper-reflective cholesteric liquid crystals,” Adv. Mater. (Deerfield Beach Fla.)23(12), 1453–1457 (2011).
[CrossRef] [PubMed]

E. Sackmann, “Photochemically induced reversible color changes in cholesteric liquid crystals,” J. Am. Chem. Soc.93(25), 7088–7090 (1971).
[CrossRef]

W. Haas, J. Adams, and J. Wysocki, “Interaction between uv radiation and cholesteric liquid crystals,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)7(1), 371–379 (1969).
[CrossRef]

J. Adams and W. Haas, “Sensitivity of cholesteric films to ultraviolet exposure,” J. Electrochem. Soc.118(12), 2026–2028 (1971).
[CrossRef]

V. Vinvogradov, A. Khizhnyak, L. Kutulya, Y. Reznikov, and V. Resihetnyak, “Photoinduced change of cholesteric LC-pitch,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)192(1), 273–278 (1990).
[CrossRef]

M. Z. Alam, T. Yoshioka, T. Ogata, T. Nonaka, and S. Kurihara, “Influence of helical twisting power on the photoswitching behavior of chiral azobenzene compounds: applications to high-performance switching devices,” Chemistry13(9), 2641–2647 (2007).
[CrossRef] [PubMed]

R. Eelkema and B. L. Feringa, “Reversible full-range color control of a cholesteric liquid-crystalline film by using a molecular motor,” Chem. Asian J.1(3), 367–369 (2006).
[CrossRef] [PubMed]

A. Chanishvili, G. Chilaya, G. Petriashvili, and D. Sikharulidze, “Light induced effects in cholesteric mixtures with a photosensitive nematic host,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)409, 209–218 (2004).
[CrossRef]

S. Kurihara, S. Nomiyama, and T. Nonaka, “Photochemical switching between a compensated nematic phase and a twisted nematic phase by photoisomerization of chiral azobenzene molecules,” Chem. Mater.12(1), 9–12 (2000).
[CrossRef]

S. S. Choi, S. M. Morris, W. T. S. Huck, and H. J. Coles, “Simultaneous red-green-blue reflection and wavelength tuning from an achiral liquid crystal and a polymer template,” Adv. Mater. (Deerfield Beach Fla.)22(1), 53–56 (2010).
[CrossRef] [PubMed]

M. Xu and D.-K. Yang, “Dual frequency cholesteric light shutters,” Appl. Phys. Lett.70(6), 720–722 (1997).
[CrossRef]

C. A. Bailey, V. P. Tondiglia, L. V. Natarajan, M. M. Duning, R. L. Bricker, R. L. Sutherland, T. J. White, M. F. Durstock, and T. J. Bunning, “Electromechanical tuning of cholesteric liquid crystals,” J. Appl. Phys.107(1), 013105 (2010).
[CrossRef]

N. Tamaoki and T. Kamei, “Reversible photo-regulation of the properties of liquid crystals doped with photochromic compounds,” J. Photochem. Photobiol. Chem.11(2–3), 47–61 (2010).

K. G. Yager and C. J. Barrett, “Novel photo-switching using azobenzene functional materials,” J. Photochem. Photobiol. A182(3), 250–261 (2006).
[CrossRef]

O. Tsutsumi, A. Kanazawa, T. Shiono, T. Ikeda, and L.-S. Park, “Photoinduced phase transition of nematic liquid crystals with donor-acceptor azobenzenes: mechanism of the thermal recovery of the nematic phase,” Phys. Chem. Chem. Phys.1(18), 4219–4224 (1999).
[CrossRef]

U. A. Hrozhyk, S. V. Serak, N. V. Tabiryan, L. Hoke, D. M. Steeves, B. Kimball, and G. Kedziora,”Systematic study of absorption spectra of donor–acceptor azobenzene mesogenic structures,” Mol. Cryst. Liq. Cryst. 489, 257[583]–272[598] (2008).

U. A. Hrozhyk, S. V. Serak, N. V. Tabiryan, L. Hoke, D. M. Steeves, and B. R. Kimball, “Azobenzene liquid crystalline materials for efficient optical switching with pulsed and/or continuous wave laser beams,” Opt. Express18(8), 8697–8704 (2010).
[CrossRef] [PubMed]

U. Hrozhyk, S. Serak, N. Tabiryan, D. Steeves, L. Hoke, and B. Kimball, “Azobenzene liquid crystals for fast reversible optical switching and enhanced sensitivity for visible wavelengths,” Proc. SPIE7414, 74140L, (2009).
[CrossRef]

L. De Sio, S. Serak, N. Tabiryan, and C. Umeton, “Mesogenic versus non-mesogenic azo dye confined in a soft-matter template for realization of optically switchable diffraction gratings,” J. Mater. Chem.21(19), 6811–6814 (2011).
[CrossRef]

U. A. Hrozhyk, S. V. Serak, N. V. Tabiryan, T. J. White, and T. J. Bunning, “Optically switchable, rapidly relaxing cholesteric liquid crystal reflectors,” Opt. Express18(9), 9651–9657 (2010).
[CrossRef] [PubMed]

U. Hrozhyk, S. Serak, N. Tabiryan, and T. J. Bunning, “Wide temperature range azobenzene nematic and smectic LC materials,” Mol. Cryst. Liq. Cryst. (Phila. Pa.)454(1), 235/[637]–245/[647] (2006).
[CrossRef]

N. V. Tabiryan, S. V. Serak, and V. A. Grozhik, “Photoinduced critical opalescence and reversible all-optical switching in photosensitive liquid crystals,” J. Opt. Soc. Am. B20(3), 538–544 (2003).
[CrossRef]

U. A. Hrozhyk, S. V. Serak, N. V. Tabiryan, and T. J. Bunning, “Optical Tuning of the Reflection of Cholesterics Doped with Azobenzene Liquid Crystals,” Adv. Funct. Mater.17(11), 1735–1742 (2007).
[CrossRef]

S. Serak, N. Tabiryan, and T. Bunning, “Nonlinear transmission of photosensitive cholesteric liquid crystals due to spectral bandwidth auto-tuning or restoration,” J. Nonlinear Opt. Phys. Mater.16(04), 471–483 (2007).
[CrossRef]

U. Hrozhyk, S. Serak, N. Tabiryan, L. Hoke, D. M. Steeves, G. Kedziora, and B. Kimball, “High optical nonlinearity of azobenzene liquid crystals for short laser pulses,” Proc. SPIE7050, 705007 (2008).

S. Serak and N. Tabiryan, “Microwatt power optically controlled spatial solitons in azobenzene liquid crystals,” Proc. SPIE6332, 63320Y1–63320Y13 (2006).

Supplementary Material (3)

» Media 1: MPG (2054 KB)     
» Media 2: MPG (2530 KB)     
» Media 3: MPG (2650 KB)     

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Figures (8)

Fig. 1
Fig. 1

Schematic of the experimental setup: NDF, set of neutral density filters; QW, quarter waveplate; BS1 and BS2, beam splitters; PM1 – PM3, power meters.

Fig. 2
Fig. 2

Absorption spectra of 3.1-μm thick planar NLC cell CPND-8(10%)/5CB measured (1) before and (2) during an exposure to a blue laser beam of 473 nm wavelength and 35 mW/cm2 power density. The inset shows the chemical structure of CPND series azo dyes: R = C7H15 for CPND-7 and R = C8H17 for CPND-8.

Fig. 3
Fig. 3

Reflection spectra for 5-μm thick CLC cells in the blue-green portion of the pectrum: 1 – CLC-1, 2 – CLC-2; 3 – CLC-3. Dotted curve corresponds to absorption spectrum of the CPND azo dye.

Fig. 4
Fig. 4

Intensity of reflected light as a function of time for response (■) and relaxation (○) of CLC bandgaps with laser beams of different wavelengths: (a) 458 nm (CLC-1) (Media 1), (b) 488 nm (CLC-2) (Media 2), and (c) 532 nm (CLC-3) (Media 3). The intensity of the beam is 28 mW/cm2 in (a) and (b), and 65 mW/cm2 in (c).

Fig. 5
Fig. 5

Transmission (T) and reflection (R) coefficients as a function of the input beam power: (a) corresponds to the CLC-1 subject to circularly polarized 458 nm laser irradiation; (b) CLC-2 with 488 nm irradiation; and (c) CLC-3 with 532 laser irradiation.

Fig. 6
Fig. 6

Response time of (a) reflection and (b) transmission vs power of laser beams of different wavelengths.

Fig. 7
Fig. 7

The ratio of the response times for transmission and reflection obtained for CLC-2 exposed to the blue laser beam (488 nm).

Fig. 8
Fig. 8

Periodic switching between reflective and transmittive states of CLC-2 (5-μm thick) with the blue laser beam (488 nm).

Tables (1)

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Table 1 Material Compositions used in the Study and Their Optical Properties

Equations (3)

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σc> ρ C P τI ( T c T o ).
δQ(T,c)= Q T δT+ Q C δc,
δT Q 0 + i f c.

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