Abstract

A variable optical attenuator (VOA) based on polymer stabilized twisted nematic (PSTN) liquid crystal (LC) is demonstrated. Comparing with the normal twisted nematic LC-based VOA, PSTN exhibits a much faster response time. Moreover, the polymer networks effectively eliminate the backflow effect which exists in the normal TNLC cell. The attenuation mechanism of the PSTN LC was studied. Both polarization rotation and light scattering effects are found to contribute to the optical attenuation. The ratio between these two mechanisms can be adjusted by changing the polymer concentration and polymer network domain size.

© 2004 Optical Society of America

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References

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  1. U. Efron, S. T. Wu, and T. D. Bates, �??Nematic liquid crystals for spatial light modulators: recent studies,�?? J. Opt. Soc. Am. B 3, 247-252 (1986).
    [CrossRef]
  2. R. Ozaki, T. Matsui, M. Ozaki, K. Yoshino, K, "Electrically color-tunable defect mode lasing in one-dimensional photonic-band-gap system containing liquid crystal," Appl. Phys. Lett. 82, 3593-3595 (2003).
    [CrossRef]
  3. S. P. Kotova, M. Yu. Kvashnin, M. A. Rakhmatulin, O. A. Zayakin, I. R. Guralnik, N. A. Klimov, P. Clark, G. D. Love, A. F. Naumov, C. D. Saunter, M. Yu. Loktev, G. V. Vdovin, and L. V. Toporkova, �??Modal liquid crystal wavefront corrector,�?? Opt. Express 10, 1258-1272 (2002). <a href="http://www.opticsexpress.org/abstract.cfm?URI=OPEX-10-22-1258">http://www.opticsexpress.org/abstract.cfm?URI=OPEX-10-22-1258</a>.
    [CrossRef] [PubMed]
  4. J. J. Pan, H. Wu, W. Wang, X. Qiu, and J. Jiang, �??Temperature independent, accurate LC VOA through electric feedback control,�?? in Proceedings of National Fiber Optics Engineers Conference (Telcordia, Orlando, Florida, 2003), pp. 943-949.
  5. C. Mao, M. Xu, W. Feng, T. Huang, K. Wu, and J. Wu, �??Liquid-crystal applications in optical tecommunication,�?? in Liquid Crystal Materials, Devices, and Applications IX, L. C. Chen, ed., Proc. SPIE 5003 121-129 (2003).
  6. I. C. Khoo and S. T. Wu, Optics and Nonlinear Nonlinear Optics of Liquid Crystals (World Scientific, Singapore, 1993), Chap. 2.
    [CrossRef]
  7. J. L. West, G. Zhang, and A. Glushchenko, �??Stressed liquid crystals for electrically controlled fast shift of phase retardation,�?? Soc. Information Display, Tech. Digest 34, 1469-1471 (2003).
  8. S. T. Wu and D. K. Yang, Reflective Liquid Crystal Displays (Wiley, New York, 2001), Chap. 10.
  9. Y. H. Fan, Y. H. Lin, H. Ren, S. Gauza, and S. T. Wu, �??Fast-response and scattering-free polymer network liquid crystals for infrared light modulators,�?? Appl. Phys. Lett. 84, 1233-1235 (2004).
    [CrossRef]
  10. C. H. Gooch and H. A. Tarry, �??The optical properties of twisted nematic liquid crystal structures with twisted angles 90°,�?? J. Phys. D. 8, 1575-1584 (1975).
    [CrossRef]
  11. N. J. Smith, M. D. Tillin, and J. R. Sambles, �??Direct optical qualification of backflow in a 90° twisted nematic cell,�?? Phys. Rev. Lett. 88, 088301 (2002).
    [CrossRef] [PubMed]
  12. C. Z. Van Doorn, �??Dynamic behavior of twisted nematic liquid-crystal layers in switched fields,�?? J. Appl. Phys. 46, 3738-3745 (1975).
    [CrossRef]
  13. R. A. M. Hikmet, �??Electrically induced light scattering from anisotropic gels,�?? J. Appl. Phys. 68, 4406-4412 (1990).
    [CrossRef]
  14. F. Du, S. Gauza, and S. T. Wu, �??Influence of curing temperature and high birefringence on the properties of polymer-stabilized liquid crystals,�?? Opt. Express 11, 2891-2896 (2003). <a href="http://www.opticsexpress.org/abstract.cfm?URI=OPEX-11-22-2891">http://www.opticsexpress.org/abstract.cfm?URI=OPEX-11-22-2891</a>.
    [CrossRef] [PubMed]
  15. S. Gauza, H. Wang, C. H. Wen, S. T. Wu, A. Seed, and R. Dabrowski, �??High birefringence isothiocyanato tolane liquid crystals,�?? Jpn. J. Appl. Phys. 42, 3463-3466 (2003).
    [CrossRef]

Appl. Phys. Lett.

R. Ozaki, T. Matsui, M. Ozaki, K. Yoshino, K, "Electrically color-tunable defect mode lasing in one-dimensional photonic-band-gap system containing liquid crystal," Appl. Phys. Lett. 82, 3593-3595 (2003).
[CrossRef]

Y. H. Fan, Y. H. Lin, H. Ren, S. Gauza, and S. T. Wu, �??Fast-response and scattering-free polymer network liquid crystals for infrared light modulators,�?? Appl. Phys. Lett. 84, 1233-1235 (2004).
[CrossRef]

J. Appl. Phys.

C. Z. Van Doorn, �??Dynamic behavior of twisted nematic liquid-crystal layers in switched fields,�?? J. Appl. Phys. 46, 3738-3745 (1975).
[CrossRef]

R. A. M. Hikmet, �??Electrically induced light scattering from anisotropic gels,�?? J. Appl. Phys. 68, 4406-4412 (1990).
[CrossRef]

J. Opt. Soc. Am. B

J. Phys. D.

C. H. Gooch and H. A. Tarry, �??The optical properties of twisted nematic liquid crystal structures with twisted angles 90°,�?? J. Phys. D. 8, 1575-1584 (1975).
[CrossRef]

Jpn. J. Appl. Phys.

S. Gauza, H. Wang, C. H. Wen, S. T. Wu, A. Seed, and R. Dabrowski, �??High birefringence isothiocyanato tolane liquid crystals,�?? Jpn. J. Appl. Phys. 42, 3463-3466 (2003).
[CrossRef]

Opt. Express

Phys. Rev. Lett.

N. J. Smith, M. D. Tillin, and J. R. Sambles, �??Direct optical qualification of backflow in a 90° twisted nematic cell,�?? Phys. Rev. Lett. 88, 088301 (2002).
[CrossRef] [PubMed]

Proc Nat. Fiber Optics Engineers Conf.

J. J. Pan, H. Wu, W. Wang, X. Qiu, and J. Jiang, �??Temperature independent, accurate LC VOA through electric feedback control,�?? in Proceedings of National Fiber Optics Engineers Conference (Telcordia, Orlando, Florida, 2003), pp. 943-949.

Proc. SPIE

C. Mao, M. Xu, W. Feng, T. Huang, K. Wu, and J. Wu, �??Liquid-crystal applications in optical tecommunication,�?? in Liquid Crystal Materials, Devices, and Applications IX, L. C. Chen, ed., Proc. SPIE 5003 121-129 (2003).

Tech. Digest

J. L. West, G. Zhang, and A. Glushchenko, �??Stressed liquid crystals for electrically controlled fast shift of phase retardation,�?? Soc. Information Display, Tech. Digest 34, 1469-1471 (2003).

Other

S. T. Wu and D. K. Yang, Reflective Liquid Crystal Displays (Wiley, New York, 2001), Chap. 10.

I. C. Khoo and S. T. Wu, Optics and Nonlinear Nonlinear Optics of Liquid Crystals (World Scientific, Singapore, 1993), Chap. 2.
[CrossRef]

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Figures (6)

Fig. 1.
Fig. 1.

A TN LC based variable optical attenuator modeled by Zemax optical simulation software.

Fig. 2.
Fig. 2.

Voltage-dependent transmittance of a TN LC based VOA. λ=1.55 µm.

Fig. 3.
Fig. 3.

Time dependent transmittance showing the VOA’s dynamic response under difference driving voltage. The solid black curve, dashed red curve and dash-dot blue curve correspond to 2.5 V, 10 V and 25 V, respectively.

Fig. 4.
Fig. 4.

Voltage dependent transmittance of a PSTN LC-based VOA.

Fig. 5.
Fig. 5.

Time dependent transmittance of a PSTNLC based VOA under difference driving voltages. The solid black curve and the dashed blue curve correspond to 20 V and 25 V, respectively.

Fig. 6.
Fig. 6.

The measured light scattering of a PSTN LC cell as a function of the applied voltage.

Tables (1)

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Table 1. Comparison of optical response times at different driving voltages.

Equations (1)

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{ τ off = γ 1 d 2 K 22 π 2 τ on = τ off ( V V th ) 2 1

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