Abstract

Cholesteric liquid crystal (CLC) application for tunable lasing devices has become a subject of study for many research groups. In particular, embedding the liquid crystal in an elastomer allows tunability by simple mechanical stretching. Here we report a study on the dependence of the selective reflection band on the stretching together with measurements of film relaxation after stretching, and we try to discuss and elucidate the role of crosslinking in the polymer matrix. We obtained laser devices made with cholesteric liquid crystal elastomers in a three-layer configuration, where an isotropic layer containing a laser dye is sandwiched between two CLC elastomers: in this work we show some preliminary but quantitative results on laser tunability.

© 2008 Optical Society of America

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  1. I. D. W. Samuel and G. A. Turnbull, "Organic semiconductor lasers," Chem. Rev. 107, 1272-1295 (2007).
    [CrossRef] [PubMed]
  2. A. D. Ford, S. M. Morris, and H. J. Coles, "Photonics and lasing in liquid crystals," Mater. Today 9, 36-42 (2006).
    [CrossRef]
  3. M. Warner and E. M. Terentjev, Liquid Crystal Elastomers (Oxford science publications, 2003).
  4. P. Xie and R. Zhang, "Liquid crystal elastomers, networks and gels: advanced smart materials," J. Mater. Chem. 15, 2529-2550 (2005).
    [CrossRef]
  5. K. D. Harris, R. Cuypers, P. Scheibe, C. L. van Oosten, C. W. M. Bastiaansen, J. Lubb, and D. J. Broer, "Large amplitude light-induced motion in high elastic modulus polymer actuators," J. Mater. Chem. 15, 5043-5048 (2005).
    [CrossRef]
  6. M. Warner, E. M. Terentjev, R. B. Meyer, and Y. Mao, "Untwisting of a cholesteric elastomer by a mechanical field," Phys. Rev. Lett. 85, 2320-2323 (2000).
    [CrossRef] [PubMed]
  7. P. A. Bermel and M. Warner, "Photonic band structure of cholesteric elastomers," Phys. Rev. E 65, 056614 (2002).
    [CrossRef]
  8. P. Cicuta, A. R. Tajbakhsh, and E. M. Terentjev, "Evolution of photonic structure on deformation of cholesteric elastomers," Phys. Rev. E 65, 051704 (2002).
    [CrossRef]
  9. P. Cicuta, A. R. Tajbakhsh, and E. M. Terentjev, "Photonic gaps in cholesteric elastomers under deformation," Phys. Rev. E 70, 011703 (2004).
    [CrossRef]
  10. V. I. Kopp, Z. Q. Zhang, and A. Z. Genack, "Lasing in chiral photonic structures," Prog. Quantum Electron. 27, 369-416 (2003).
    [CrossRef]
  11. Y. Huang, Y. Zhou, and S. T. Wu, "Spatially tunable laser emission in dye-doped photonic liquid crystals," Appl. Phys. Lett. 88, 011107 (2005).
    [CrossRef]
  12. Y. Huang, Y. Zhou, C. Doyle, and S. T. Wu, "Tuning the photonic band gap in cholesteric liquid crystals by temperature-dependent dopant solubility," Opt. Express 14, 1236-1242 (2006).
    [CrossRef] [PubMed]
  13. M. Kasano, M. Ozaki, and K. Yoshino, "Electrically tunable waveguide laser based on ferroelectric liquid crystal," Appl. Phys. Lett. 82, 4026-4028 (2003).
    [CrossRef]
  14. A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, A. Mazzulla, R. Gimenez, L. Oriol, and M. Pinol, "Widely tunable ultraviolet-visible liquid crystal laser," Appl. Phys. Lett. 86, 051107 (2005).
    [CrossRef]
  15. G. S. Chilaya, "Light-controlled change in the helical pitch and broadband tunable cholesteric liquid-crystal lasers," Crystallogr. Rep. 51, S108-S118 (2006).
    [CrossRef]
  16. P. V. Shibaev, R. L. Sanford, D. Chiappetta, V. Milner, A. Genack, and A. Bobrovsky, "Light controllable tuning and switching of lasing in chiral liquid crystals," Opt. Express 13, 2358-2363 (2005).
    [CrossRef] [PubMed]
  17. 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, 161120 (2005).
    [CrossRef]
  18. A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, A. Mazzulla, and L. Oriol, "Phototunable lasing in dye-doped cholesteric liquid crystals," Appl. Phys. Lett. 83, 5353-5355 (2003).
    [CrossRef]
  19. A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, and A. Mazzulla, "Lasing in dye-doped cholesteric liquid crystals: two new strategies of tuning," Adv. Mat. 16, 791-794 (2004).
    [CrossRef]
  20. G. Chilaya, A. Chanishvili, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, A. Mazzulla, and P. V. Shibaev, "Reversible tuning of lasing in cholesteric liquid crystals controlled by light emitting diodes," Adv. Mat. 19, 565-568 (2007).
    [CrossRef]
  21. P. V. Shibaev, D. Chiappetta, R. L. Sanford, P. Palffy-Muhoray, M. Moreira, W. Cao, and M. M. Green, "Color Changing Cholesteric Polymer Films Sensitive to Amino Acids," Macromol. 39, 3986-3992 (2006).
    [CrossRef]
  22. H. Finkelmann, S. T. Kim, A. Munoz, P. Palffy-Muhoray, and B. Taheri, "Tunable mirrorless lasing in cholesteric liquid crystalline elastomers," Adv. Mater. 13, 1069-1072 (2001).
    [CrossRef]
  23. J. Schmidtke, S. Kniesel, and H. Finkelmann, "Probing the Photonic Properties of a Cholesteric Elastomer under Biaxial Stress," Macromol. 38, 1357-1363 (2005).
    [CrossRef]
  24. Z. Li, Z. Zhang, A. Scherer, and D. Psaltis, "Mechanically tunable optofluidic distributed feedback dye laser," Opt. Express 14, 10494-10499 (2006).
    [CrossRef] [PubMed]
  25. H. Finkelmann, "Liquid crystalline polymers," Angew. Chem. Int. Ed. Eng. 26, 816-824 (1987).
    [CrossRef]
  26. S. T. Kim and H. Finkelmann, "Cholesteric liquid single-crystal elastomers obtained by the anisotropic deswelling method," Macromol. Rapid. Commun. 22, 429-433 (2001).
    [CrossRef]
  27. S. Courty, A. R. Tajbakhsh, and E. M. Terentjev, "Chirality transfer and stereoselectivity of imprinted cholesteric networks," Phys. Rev. E 73011803 (2006).
    [CrossRef]
  28. J. V. Crivello, B. Falk, and M. R. ZoncaJr, "Photoinduced cationic ring-opening frontal polymerizations of oxetanes and oxiranes," J. Polym. Sci. Pol. Chem. 42, 1630-1646 (2004).
    [CrossRef]
  29. D. R. Skinner and R. E. Whitcher, "Measurement of the radius of a high-power laser beam near the focus of a lens," J. Phys. E Sci. Instrum. 5, 237-238 (1972).
    [CrossRef]
  30. J. Schmidtke and W. Stille, "Photonic defect modes in cholesteric liquid crystal films," Eur. Phys. J. E 12, 553-564 (2003).
    [CrossRef]
  31. J. Schmidtke, W. Stille, and H. Finkelmann, "Defect mode emission of a dye doped cholesteric polymer network," Phys. Rev. Lett. 90, 083902 (2003).
    [CrossRef] [PubMed]
  32. M. H. Song, N. Y. Ha, K. Amemiya, B. Park, Y. Takanishi, K. Ishikawa, J. W. Wu, S. Nishimura, T. Toyooka, and H. Takezoe, "Defect-mode lasing with lowered threshold in three-layered hetero-cholesteric liquid-crystal structure," Adv. Mater. 18, 193-197 (2006).
    [CrossRef]
  33. Y. Takanishi, N. Tomoe, N. Y. Ha, T. Toyooka, S. Nishimura, K. Ishikawa, and H. Takezoe, "Defect-Mode Lasing from a Three-Layered Helical Cholesteric Liquid Crystal Structure," Jpn. J. Appl. Phys. 46, 3510-3513 (2007).
    [CrossRef]

2007 (3)

I. D. W. Samuel and G. A. Turnbull, "Organic semiconductor lasers," Chem. Rev. 107, 1272-1295 (2007).
[CrossRef] [PubMed]

G. Chilaya, A. Chanishvili, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, A. Mazzulla, and P. V. Shibaev, "Reversible tuning of lasing in cholesteric liquid crystals controlled by light emitting diodes," Adv. Mat. 19, 565-568 (2007).
[CrossRef]

Y. Takanishi, N. Tomoe, N. Y. Ha, T. Toyooka, S. Nishimura, K. Ishikawa, and H. Takezoe, "Defect-Mode Lasing from a Three-Layered Helical Cholesteric Liquid Crystal Structure," Jpn. J. Appl. Phys. 46, 3510-3513 (2007).
[CrossRef]

2006 (7)

M. H. Song, N. Y. Ha, K. Amemiya, B. Park, Y. Takanishi, K. Ishikawa, J. W. Wu, S. Nishimura, T. Toyooka, and H. Takezoe, "Defect-mode lasing with lowered threshold in three-layered hetero-cholesteric liquid-crystal structure," Adv. Mater. 18, 193-197 (2006).
[CrossRef]

S. Courty, A. R. Tajbakhsh, and E. M. Terentjev, "Chirality transfer and stereoselectivity of imprinted cholesteric networks," Phys. Rev. E 73011803 (2006).
[CrossRef]

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

Y. Huang, Y. Zhou, C. Doyle, and S. T. Wu, "Tuning the photonic band gap in cholesteric liquid crystals by temperature-dependent dopant solubility," Opt. Express 14, 1236-1242 (2006).
[CrossRef] [PubMed]

Z. Li, Z. Zhang, A. Scherer, and D. Psaltis, "Mechanically tunable optofluidic distributed feedback dye laser," Opt. Express 14, 10494-10499 (2006).
[CrossRef] [PubMed]

P. V. Shibaev, D. Chiappetta, R. L. Sanford, P. Palffy-Muhoray, M. Moreira, W. Cao, and M. M. Green, "Color Changing Cholesteric Polymer Films Sensitive to Amino Acids," Macromol. 39, 3986-3992 (2006).
[CrossRef]

A. D. Ford, S. M. Morris, and H. J. Coles, "Photonics and lasing in liquid crystals," Mater. Today 9, 36-42 (2006).
[CrossRef]

2005 (7)

P. Xie and R. Zhang, "Liquid crystal elastomers, networks and gels: advanced smart materials," J. Mater. Chem. 15, 2529-2550 (2005).
[CrossRef]

K. D. Harris, R. Cuypers, P. Scheibe, C. L. van Oosten, C. W. M. Bastiaansen, J. Lubb, and D. J. Broer, "Large amplitude light-induced motion in high elastic modulus polymer actuators," J. Mater. Chem. 15, 5043-5048 (2005).
[CrossRef]

Y. Huang, Y. Zhou, and S. T. Wu, "Spatially tunable laser emission in dye-doped photonic liquid crystals," Appl. Phys. Lett. 88, 011107 (2005).
[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, 161120 (2005).
[CrossRef]

J. Schmidtke, S. Kniesel, and H. Finkelmann, "Probing the Photonic Properties of a Cholesteric Elastomer under Biaxial Stress," Macromol. 38, 1357-1363 (2005).
[CrossRef]

P. V. Shibaev, R. L. Sanford, D. Chiappetta, V. Milner, A. Genack, and A. Bobrovsky, "Light controllable tuning and switching of lasing in chiral liquid crystals," Opt. Express 13, 2358-2363 (2005).
[CrossRef] [PubMed]

A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, A. Mazzulla, R. Gimenez, L. Oriol, and M. Pinol, "Widely tunable ultraviolet-visible liquid crystal laser," Appl. Phys. Lett. 86, 051107 (2005).
[CrossRef]

2004 (3)

J. V. Crivello, B. Falk, and M. R. ZoncaJr, "Photoinduced cationic ring-opening frontal polymerizations of oxetanes and oxiranes," J. Polym. Sci. Pol. Chem. 42, 1630-1646 (2004).
[CrossRef]

A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, and A. Mazzulla, "Lasing in dye-doped cholesteric liquid crystals: two new strategies of tuning," Adv. Mat. 16, 791-794 (2004).
[CrossRef]

P. Cicuta, A. R. Tajbakhsh, and E. M. Terentjev, "Photonic gaps in cholesteric elastomers under deformation," Phys. Rev. E 70, 011703 (2004).
[CrossRef]

2003 (5)

V. I. Kopp, Z. Q. Zhang, and A. Z. Genack, "Lasing in chiral photonic structures," Prog. Quantum Electron. 27, 369-416 (2003).
[CrossRef]

A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, A. Mazzulla, and L. Oriol, "Phototunable lasing in dye-doped cholesteric liquid crystals," Appl. Phys. Lett. 83, 5353-5355 (2003).
[CrossRef]

J. Schmidtke and W. Stille, "Photonic defect modes in cholesteric liquid crystal films," Eur. Phys. J. E 12, 553-564 (2003).
[CrossRef]

J. Schmidtke, W. Stille, and H. Finkelmann, "Defect mode emission of a dye doped cholesteric polymer network," Phys. Rev. Lett. 90, 083902 (2003).
[CrossRef] [PubMed]

M. Kasano, M. Ozaki, and K. Yoshino, "Electrically tunable waveguide laser based on ferroelectric liquid crystal," Appl. Phys. Lett. 82, 4026-4028 (2003).
[CrossRef]

2002 (2)

P. A. Bermel and M. Warner, "Photonic band structure of cholesteric elastomers," Phys. Rev. E 65, 056614 (2002).
[CrossRef]

P. Cicuta, A. R. Tajbakhsh, and E. M. Terentjev, "Evolution of photonic structure on deformation of cholesteric elastomers," Phys. Rev. E 65, 051704 (2002).
[CrossRef]

2001 (2)

H. Finkelmann, S. T. Kim, A. Munoz, P. Palffy-Muhoray, and B. Taheri, "Tunable mirrorless lasing in cholesteric liquid crystalline elastomers," Adv. Mater. 13, 1069-1072 (2001).
[CrossRef]

S. T. Kim and H. Finkelmann, "Cholesteric liquid single-crystal elastomers obtained by the anisotropic deswelling method," Macromol. Rapid. Commun. 22, 429-433 (2001).
[CrossRef]

2000 (1)

M. Warner, E. M. Terentjev, R. B. Meyer, and Y. Mao, "Untwisting of a cholesteric elastomer by a mechanical field," Phys. Rev. Lett. 85, 2320-2323 (2000).
[CrossRef] [PubMed]

1987 (1)

H. Finkelmann, "Liquid crystalline polymers," Angew. Chem. Int. Ed. Eng. 26, 816-824 (1987).
[CrossRef]

1972 (1)

D. R. Skinner and R. E. Whitcher, "Measurement of the radius of a high-power laser beam near the focus of a lens," J. Phys. E Sci. Instrum. 5, 237-238 (1972).
[CrossRef]

Adv. Mat. (2)

A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, and A. Mazzulla, "Lasing in dye-doped cholesteric liquid crystals: two new strategies of tuning," Adv. Mat. 16, 791-794 (2004).
[CrossRef]

G. Chilaya, A. Chanishvili, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, A. Mazzulla, and P. V. Shibaev, "Reversible tuning of lasing in cholesteric liquid crystals controlled by light emitting diodes," Adv. Mat. 19, 565-568 (2007).
[CrossRef]

Adv. Mater. (2)

H. Finkelmann, S. T. Kim, A. Munoz, P. Palffy-Muhoray, and B. Taheri, "Tunable mirrorless lasing in cholesteric liquid crystalline elastomers," Adv. Mater. 13, 1069-1072 (2001).
[CrossRef]

M. H. Song, N. Y. Ha, K. Amemiya, B. Park, Y. Takanishi, K. Ishikawa, J. W. Wu, S. Nishimura, T. Toyooka, and H. Takezoe, "Defect-mode lasing with lowered threshold in three-layered hetero-cholesteric liquid-crystal structure," Adv. Mater. 18, 193-197 (2006).
[CrossRef]

Angew. Chem. Int. Ed. Eng. (1)

H. Finkelmann, "Liquid crystalline polymers," Angew. Chem. Int. Ed. Eng. 26, 816-824 (1987).
[CrossRef]

Appl. Phys. Lett. (5)

Y. Huang, Y. Zhou, and S. T. Wu, "Spatially tunable laser emission in dye-doped photonic liquid crystals," Appl. Phys. Lett. 88, 011107 (2005).
[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, 161120 (2005).
[CrossRef]

A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, A. Mazzulla, and L. Oriol, "Phototunable lasing in dye-doped cholesteric liquid crystals," Appl. Phys. Lett. 83, 5353-5355 (2003).
[CrossRef]

M. Kasano, M. Ozaki, and K. Yoshino, "Electrically tunable waveguide laser based on ferroelectric liquid crystal," Appl. Phys. Lett. 82, 4026-4028 (2003).
[CrossRef]

A. Chanishvili, G. Chilaya, G. Petriashvili, R. Barberi, R. Bartolino, G. Cipparrone, A. Mazzulla, R. Gimenez, L. Oriol, and M. Pinol, "Widely tunable ultraviolet-visible liquid crystal laser," Appl. Phys. Lett. 86, 051107 (2005).
[CrossRef]

Chem. Rev. (1)

I. D. W. Samuel and G. A. Turnbull, "Organic semiconductor lasers," Chem. Rev. 107, 1272-1295 (2007).
[CrossRef] [PubMed]

Crystallogr. Rep. (1)

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

Eur. Phys. J. E (1)

J. Schmidtke and W. Stille, "Photonic defect modes in cholesteric liquid crystal films," Eur. Phys. J. E 12, 553-564 (2003).
[CrossRef]

J. Mater. Chem. (2)

P. Xie and R. Zhang, "Liquid crystal elastomers, networks and gels: advanced smart materials," J. Mater. Chem. 15, 2529-2550 (2005).
[CrossRef]

K. D. Harris, R. Cuypers, P. Scheibe, C. L. van Oosten, C. W. M. Bastiaansen, J. Lubb, and D. J. Broer, "Large amplitude light-induced motion in high elastic modulus polymer actuators," J. Mater. Chem. 15, 5043-5048 (2005).
[CrossRef]

J. Phys. E Sci. Instrum. (1)

D. R. Skinner and R. E. Whitcher, "Measurement of the radius of a high-power laser beam near the focus of a lens," J. Phys. E Sci. Instrum. 5, 237-238 (1972).
[CrossRef]

J. Polym. Sci. Pol. Chem. (1)

J. V. Crivello, B. Falk, and M. R. ZoncaJr, "Photoinduced cationic ring-opening frontal polymerizations of oxetanes and oxiranes," J. Polym. Sci. Pol. Chem. 42, 1630-1646 (2004).
[CrossRef]

Jpn. J. Appl. Phys. (1)

Y. Takanishi, N. Tomoe, N. Y. Ha, T. Toyooka, S. Nishimura, K. Ishikawa, and H. Takezoe, "Defect-Mode Lasing from a Three-Layered Helical Cholesteric Liquid Crystal Structure," Jpn. J. Appl. Phys. 46, 3510-3513 (2007).
[CrossRef]

Macromol. (2)

P. V. Shibaev, D. Chiappetta, R. L. Sanford, P. Palffy-Muhoray, M. Moreira, W. Cao, and M. M. Green, "Color Changing Cholesteric Polymer Films Sensitive to Amino Acids," Macromol. 39, 3986-3992 (2006).
[CrossRef]

J. Schmidtke, S. Kniesel, and H. Finkelmann, "Probing the Photonic Properties of a Cholesteric Elastomer under Biaxial Stress," Macromol. 38, 1357-1363 (2005).
[CrossRef]

Macromol. Rapid. Commun. (1)

S. T. Kim and H. Finkelmann, "Cholesteric liquid single-crystal elastomers obtained by the anisotropic deswelling method," Macromol. Rapid. Commun. 22, 429-433 (2001).
[CrossRef]

Mater. Today (1)

A. D. Ford, S. M. Morris, and H. J. Coles, "Photonics and lasing in liquid crystals," Mater. Today 9, 36-42 (2006).
[CrossRef]

Opt. Express (3)

Phys. Rev. E (4)

P. A. Bermel and M. Warner, "Photonic band structure of cholesteric elastomers," Phys. Rev. E 65, 056614 (2002).
[CrossRef]

P. Cicuta, A. R. Tajbakhsh, and E. M. Terentjev, "Evolution of photonic structure on deformation of cholesteric elastomers," Phys. Rev. E 65, 051704 (2002).
[CrossRef]

P. Cicuta, A. R. Tajbakhsh, and E. M. Terentjev, "Photonic gaps in cholesteric elastomers under deformation," Phys. Rev. E 70, 011703 (2004).
[CrossRef]

S. Courty, A. R. Tajbakhsh, and E. M. Terentjev, "Chirality transfer and stereoselectivity of imprinted cholesteric networks," Phys. Rev. E 73011803 (2006).
[CrossRef]

Phys. Rev. Lett. (2)

M. Warner, E. M. Terentjev, R. B. Meyer, and Y. Mao, "Untwisting of a cholesteric elastomer by a mechanical field," Phys. Rev. Lett. 85, 2320-2323 (2000).
[CrossRef] [PubMed]

J. Schmidtke, W. Stille, and H. Finkelmann, "Defect mode emission of a dye doped cholesteric polymer network," Phys. Rev. Lett. 90, 083902 (2003).
[CrossRef] [PubMed]

Prog. Quantum Electron. (1)

V. I. Kopp, Z. Q. Zhang, and A. Z. Genack, "Lasing in chiral photonic structures," Prog. Quantum Electron. 27, 369-416 (2003).
[CrossRef]

Other (1)

M. Warner and E. M. Terentjev, Liquid Crystal Elastomers (Oxford science publications, 2003).

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Figures (10)

Fig. 1.
Fig. 1.

A schematic view of CLC elastomer under uniaxial strain imposed along x. Contraction of z dimension, λzz , leads to a continuous shift of the photonic bandgap.

Fig. 2.
Fig. 2.

Director angle ϕ against position along the pitch z, for a system with anisotropy r=1.2. Without stress, at λ=1, ϕ increases linearly with the position q̃z. As λ increases, the curvature changes until the point when the system undergoes a chirality-loss transition (shown by a arrow), at which the original helical structure becomes a non-chiral periodic structure.

Fig. 3.
Fig. 3.

(a) Components and the reaction scheme of UV-crosslinkable choleseric polysiloxane; (b) Components and the reaction scheme of the dye-containing modified side-chain polysiloxane.

Fig. 4.
Fig. 4.

Scheme of the three layer sandwiched configuration.

Fig. 5.
Fig. 5.

Transmittance spectra of non-crosslinked and crosslinked CLC films under uniaxial strain, under right- and left handed circularly polarized incident light (R* and L* plots, respectively). L* spectra show a pronounced selective reflection band in the stretched crosslinked CLC elastomer, whereas no L* peak is seen in the non cross-linked CLC polymer.

Fig. 6.
Fig. 6.

Peak height of the selective reflection band against uniaxial elongation. On stretching, the peak height of L* polarization in crosslinked CLC elastomers becomes comparable with the R* polarization reflection, showing that the original helical chirality is lost in favor of a non-chiral periodical texture. No significant change is seen in the non-crosslinked CLC polymer reflection intensity. The lines are just a guide for the eye.

Fig. 7.
Fig. 7.

The contraction of cholesteric helix λzz against imposed uniaxial strain λxx . The non cross-linked CLC polymer plots on the line of λ -0.5 xx showing the isotropic deformation, whereas the cross-linked CLC polymer plots on the line of λ -0.38 xx showing the anisotropic deformation.

Fig. 8.
Fig. 8.

Relaxation of the contracted helix under uniaxial strain after the samples of non-crosslinked and weakly crosslinked CLC polymer were instantaneously stretched by 70%. The plot shows the normalized shift in the R* selective reflection peak position; the data is fitted by a double exponential equation. The dashed line suggests the level that would be exhibited in the fully crosslinked CLC network.

Fig. 9.
Fig. 9.

Single mode laser emission from the CLC-MS-CLC three layer system, stretched by about 60%. Superposed is the transmittance spectrum of the CLC layer stretched by the same amount between silicone supports. The laser emission intensity is expressed in arbitrary units.

Fig. 10.
Fig. 10.

Wavelength of the primary emission line is plotted against sample elongation (*), and compared with the peak wavelength λc of the cholesteric selective reflection gap (△). Horizontal dotted lines show the range of emission spectrum of Rhodamine B (RhB) where the emission intensity is more than 50% of its maximum value (585–650 nm).

Equations (3)

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tan 2 ϕ = 2 λ 1 4 ( r 1 ) sin 2 q ˜ z ( r 1 ) ( λ 2 + λ 3 2 ) cos 2 q ˜ z + ( r + 1 ) ( λ 2 λ 3 2 )
Δ λ ( t ) = λ ( I ) λ ( t ) λ ( I ) λ min ( 0 )
Δ λ ( t ) = A s e k s t + A f e k f t + B

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