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2014-05-20
Multiple Time Scales Optical Nonlinearities of Liquid Crystals for Optical-Terahertz-Microwave Applications (Invited Review)
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Progress In Electromagnetics Research, Vol. 147, 37-56, 2014
Abstract
We provide a critical account of the dynamics of laser induced refractive index changing mechanisms in nematic liquid crystals which may be useful for all-optical switching and modulation applications in the visible as well as the Terahertz and long-wavelength regime. In particular, the magnitude and response times of optical Kerr effects associated with director axis reorientation, thermal and order parameter changes, coupled flow-reorientation effects and individual molecular electronic responses are thoroughly investigated and documented, along with exemplary experimental demonstrations. Emphases are placed on identifying parameter sets that will enable all-optical switching with much faster response times compared to their conventional electro-optics counterparts.
Citation
Iam Choon Khoo, and Shuo Zhao, "Multiple Time Scales Optical Nonlinearities of Liquid Crystals for Optical-Terahertz-Microwave Applications (Invited Review)," Progress In Electromagnetics Research, Vol. 147, 37-56, 2014.
doi:10.2528/PIER14032301
References

1. Khoo, I. C. and S. T. Wu, Optics and Nonlinear Optics of Liquid Crystals, World Scientidic, Singapore, 1994.

2. Khoo, I. C., "Liquid Crystals," Wiley, NJ, 2007.

3. Khoo, I. C., "Nonlinear optics of liquid crystalline materials," Physics Report, Vol. 471, No. 5-6, 221-267, 2009.
doi:10.1016/j.physrep.2009.01.001

4. Khoo, I. C., "Extreme nonlinear optics of nematic liquid crystals," J. Opt. Soc. Am. B, Vol. 28, A45-A55, 2011.
doi:10.1364/JOSAB.28.000A45

5. Khoo, I. C., "Nonlinear optics, active plasmonics and tunable metamaterials with liquid crystals," Progress in Quantum Electronics, Vol. 38, 77-117, 2014.
doi:10.1016/j.pquantelec.2014.03.001

6. Sambles, J. R., R. Kelly, and R. F. Yang, "Metal slits and liquid crystals at microwave frequencies," Philos. Transact. A, Math. Phys. Eng. Sci., Vol. 364, No. 1847, 2733-2746, 2006.
doi:10.1098/rsta.2006.1850

7. Khoo, I. C., Y. Z. Williams, A. Diaz, K. Chen, J. A. Bossard, L. Li, D. H. Werner, E. Graugnard, J. S. King, S. Jain, C. J. Summers, and , "Liquid-crystals for tunable photonic crystals, frequency selective surfaces and negative index material development," Mole. Cryst. Liq. Cryst., Vol. 453, 309-319, 2006.
doi:10.1080/15421400600653654

8. Graugnard, E., J. S. King, S. Jain, C. J. Summers, Y. Zhang-Williams, and I. C. Khoo, "Electric field tuning of the Bragg peak in large-pore TiO2 inverse shell opals," Phys. Rev. B, Vol. 72, 233105-1-233105-4, 2005.

9. D'Alessandro, A., R. Asquini, M. Trotta, G. Gilardi, R. Beccherelli, and I. C. Khoo, "All-optical intensity modulation of near infrared light in a liquid crystal channel waveguide," Appl. Phys. Lett., Vol. 97, No. 9, 093302, 2010.
doi:10.1063/1.3483157

10. Larsen, T. T., A. Bjarklev, D. S. Hermann, and J. Broeng, "Optical devices based on liquid crystal photonic bandgap fibers," Optics Express, Vol. 11, 2589-2596, 2003.
doi:10.1364/OE.11.002589

11. Ptasinski, J., S. W. Kim, L. Pang, I.-C. Khoo, and Y. Fainman, "Optical tuning of silicon photonic structures with nematic liquid crystal claddings," Optics Letters, Vol. 38, 2008-2010, 2013.
doi:10.1364/OL.38.002008

12. Xiao, S., U. K. Chettiar, A. V. Kildishev, V. Drachev, I. C. Khoo, and V. M. Shalaev, "Tunable magnetic response of metamaterials," Appl. Phys. Lett., Vol. 95, No. 3, 033115, 2009.
doi:10.1063/1.3182857

13. Minovich, A., J. Farnell, D. N. Neshev, I. McKerracher, F. Karouta, J. Tian, D. A. Powell, I. V. Shadrivov, H. H. Tan, C. Jagadish, and Y. S. Kivshar, "Liquid crystal based nonlinear fishnet metamaterials," Appl. Phys. Lett., Vol. 100, 121113-4, 2012.

14. Zhao, Q., L. Kang, B. Du, B. Li, J. Zhou, H. Tang, X. Liang, and B. Z. Zhang, "Electrically tunable negative permeability metamaterials based on nematic liquid crystals," Appl. Phys. Lett., Vol. 90, No. 011112, 2007, and References therein.

15. Zhang, F. L., W. H. Zhang, Q. Zhao, J. B. Sun, K. P. Qiu, J. Zhou, and D. Lippens, "Electrically controllable fishnet metamaterial based on nematic liquid crystal," Optics Express, Vol. 19, 1563-1568, 2011.
doi:10.1364/OE.19.001563

16. Bossard, J. A., X. Liang, L. Li, S. Yun, D. H. Werner, B. Weiner, T. S. Mayer, P. F. Cristman, A. Diaz, and I. C. Khoo, "Tunable frequency selective surfaces and negative-zero-positive index metamaterials based on liquid crystals," IEEE Transactions on Antennas and Propagation, Vol. 56, No. 5, 1308-1320, 2008.
doi:10.1109/TAP.2008.922174

17. Wang, X., D. H. Kwon, D. H.Werner, I. C. Khoo, A. Kildishev, and V. M. Shalaev, "Tunable optical negative-index metamaterials employing anisotropic liquid crystals," Appl. Phys. Lett., Vol. 91, 143122, 2007.
doi:10.1063/1.2795345

18. Werner, D. H., D. H. Kwon, and I. C. Khoo, "Liquid crystal clad near-infrared metamaterials with tunable negative-zero-positive refractive indices," Optics Express, Vol. 15, 3342-3347, 2007.
doi:10.1364/OE.15.003342

19. Zhao, Y., Q. Z. Hao, Y. Ma, M. Q. Lu, B. X. Zhang, M. Lapsley, I. C. Khoo, and T. J. Huang, "Light-driven tunable dual band absorber with liquid-crystal-plasmonic asymmetric nanodisk array," Appl. Phys. Lett., Vol. 100, 053119, 2012.
doi:10.1063/1.3681808

20. Huang, T. J., Y. J. Liu, B. Yue, J. Liou, and I. C. Khoo, "All-optical modulation of localized surface plasmon coupling in a hybrid system composed of photo-switchable gratings and Au nanodisk arrays," Journal of Physical Chemistry, Vol. 115, No. 15, 7717-7722, 2011.

21. Hao, Q., Y. Zhao, J. B. Krishna, I. C. Khoo, and T. Huang, "Frequency-addressed tunable transmission in optically thin metallic nanohole arrays with dual-frequency liquid crystals," J. Appl. Phys., Vol. 109, 084340, 2011.
doi:10.1063/1.3581037

22. Liu, Y. J., Q. Z. Hao, J. S. T. Smalley, J. Liou, I. C. Khoo, and T. J. Huang, "A frequency-addressed plasmonic switch based on dual-frequency liquid crystals," Appl. Phys. Lett., Vol. 97, 091101, 2010.
doi:10.1063/1.3483156

23. Dickson, W., G. A. Wurtz, P. R. Evans, R. J. Pollard, and A. V. Zayats, "Electronically controlled surface plasmon dispersion and optical transmission through metallic hole arrays using liquid crystal," Nano Letts., Vol. 8, No. 1, 281-286, 2008.
doi:10.1021/nl072613g

24. Kossyrev, P. A., A. J. Yin, S. G. Cloutier, D. A. Cardimona, D. H. Huang, P. M. Alsing, and J. M. Xu, "Electric field tuning of plasmonic response of nanodot array in liquid crystal matrix," Nano Letts., Vol. 5, 1978-1981, 2005.
doi:10.1021/nl0513535

25. Daly, K. R., S. Abbott, G. D'Alessandro, D. C. Smith, and M. Kaczmarek, "Theory of hybrid photorefractive plasmonic liquid crystal cells," J. Opt. Soc. Am., Vol. 28, 1874-1881, 2011.
doi:10.1364/JOSAB.28.001874

26. Hu, W., R. Cahill, J. A. Encinar, et al. "Design and measurement of reconfigurable millimeter wave reflectarray cells with nematic liquid crystal," IEEE Transactions on Antennas and Propagation, Vol. 56, No. 10, 3112-3117, 2008.
doi:10.1109/TAP.2008.929460

27. Kuki, T., H. Fujikake, and T. Nomoto, "Microwave variable delay line using dual-frequency switching-mode liquid crystal," IEEE Trans. Microw. Theory Tech., Vol. 50, No. 11, 2604-2609, 2002.
doi:10.1109/TMTT.2002.804510

28. Dolfi, D., M. Labeyrie, P. Joffre, and J. P. Huignard, "Liquid crystal microwave phase shifter," Electron. Lett., Vol. 29, No. 10, 926-928, May 1993.
doi:10.1049/el:19930618

29. Kuki, T., H. Fujikake, T. Nomoto, and Y. Utsumi, "Design of a microwave variable delay line using liquid crystal and a study of its insertion loss," Electron. Commun. Jpn., Vol. 85, No. 2, 36-42, Feb. 2002.

30. Kamei, T., Y. Utsumi, H. Moritake, K. Toda, and H. Suzuki, "Measurements of the dielectric properties of nematic liquid crystal at 10 kHz to 40 GHz and application to a variable delay line," Electron. Commun. Jpn., Vol. 86, No. 8, 49-60, Aug. 2003.

31. Fujikake, H., T. Kuki, T. Nomoto, Y. Tsuchiya, and Y. Utsumi, "Thick polymer-stabilized liquid crystal films for microwave phase control," J. Appl. Phys., Vol. 89, 5295-5298, 2001.
doi:10.1063/1.1365081

32. Guerin, F., J. M. Chappe, P. Joffre, and D. Dolfi, "Modelling, synthesis and characterization of a millimeter-wave multilayer microstrip liquid crystal phase shifter," Jpn. J. Appl. Phys., Vol. 36, 4409-4413, 1997.
doi:10.1143/JJAP.36.4409

33. Hibbins, A. P., J. R. Sambles, C. R. Lawrence, and D. M. Robinson, "Remarkable transmission of microwaves through a wall of metallic bricks," Appl. Phys. Lett., Vol. 79, 2844-2846, 2001.
doi:10.1063/1.1412593

34. Lim, K. C., J. D. Margerum, and A. M. Lackner, "Liquid crystal millimetre wave electronic phase shifter," Appl. Phys. Lett., Vol. 69, 1065-1067, 1993.
doi:10.1063/1.108796

35. Lim, K. C., J. D. Margerum, A. M. Lackner, L. J. Miller, E. Sherman, and W. H. Smith, "Liquid crystal birefringence for millimetre wave radar," Liq. Cryst., Vol. 14, 327-337, 1993.
doi:10.1080/02678299308027647

36. Tanaka, M. and S. Sato, "Millimetre-wave de°ection properties of liquid crystal prism cells with stack-layered structure," J. Appl. Phys., Vol. 40, L1123-L1125, 2002.

37. Tanaka, M. and S. Sato, "Focusing properties of liquid crystal lens cells with stack-layered structure in the millimetre wave region," IEEE Microw. Wireless Component Lett.,, Vol. 12, 163-165, 2002.
doi:10.1109/7260.1000190

38. Kowerdzieja, R., J. Parka, and J. Krupkab, "Experimental study of thermally controlled metamaterial containing a liquid crystal layer at microwave frequencies," Liq. Cryst., Vol. 38, 743-747, 2011.
doi:10.1080/02678292.2011.571820

39. Yang, F. and J. R. Sambles, "Microwave liquid crystal wavelength selector," Appl. Phys. Lett., Vol. 79, 3717-3719, 2001.
doi:10.1063/1.1419240

40. Yang, F. and J. R. Sambles, "Microwave liquid crystal variable phase grating," Appl. Phys. Lett., Vol. 85, 2041-2043, 2004.
doi:10.1063/1.1787898

41. Li, J., S. T.Wu, S. Brugioni, R. Meucci, and S. Faetti, "Infrared refractive indices of liquid crystals," J. Appl. Phys., Vol. 97, No. 7, 073501, 2005.
doi:10.1063/1.1877815

42. Yang, C. S., C. J. Lin, R. P. Pan, C. T. Que, K. Yamamoto, M. Tani, and C. L. Pan, "The complex refractive indices of the liquid crystal mixture E7 in the terahertz frequency range," J. Opt. Soc. Am. B, Vol. 27, No. 4, 1866-1873, 2010.
doi:10.1364/JOSAB.27.001866

43. Park, H., E. P. J. Parrott, F. Fan, M. Lim, H. Han, V. G. Chigrinov, and E. Pickwell-MacPherson, "Evaluating liquid crystal properties for use in terahertz devices," Optics Express, Vol. 20, 11899-11905, 2012.
doi:10.1364/OE.20.011899

44. Wang, L., X.-W. Lin, X. Liang, J.-B. Wu, W. Hu, Z.-G. Zheng, B.-B. Jin, Y.-Q. Qin, and Y.-Q. Lu, "Large birefringence liquid crystal material in terahertz rang," Opt. Mat. Exp., Vol. 2, 1314-1319, 2012.
doi:10.1364/OME.2.001314

45. Weil, C., S. Mueller, P. Scheele, P. Best, G. LÄussem, and R. Jakoby, "Highly-anisotropic liquid-crystal mixtures for tunable microwave devices," Electron. Lett., Vol. 39, No. 24, 1732-1734, Nov. 2003.
doi:10.1049/el:20031150

46. Mueller, S., A. Penirschke, C. Damm, P. Scheele, M. Wittek, C. Weil, and R. Jakoby, "Broad-band microwave characterization of liquid crystals using a temperature-controlled coaxial transmission line," IEEE Trans. Microw. Theory Tech., Vol. 53, No. 6, 1937-1945, Jun. 2005.
doi:10.1109/TMTT.2005.848842

47. Arakawa, Y., S. Nakajima, S. M. Kang, M. Shigeta, G. Konishi, and J. Watanabe, "Design of an extremely high birefringence nematic liquid crystal based on a dinaphthyl-diacetylene mesogen," J. Mat. Chem., Vol. 22, 13908-13910, 2012, and References therein.
doi:10.1039/c2jm32448b

48. Okano, K., O. Tsutsumi, A. Shishido, and T. Ikeda, "Azotolane liquid-crystalline polymers: Huge change in birefringence by photoinduced alignment change," J. Am. Chem. Soc., Vol. 128, 15368-15369, 2006.
doi:10.1021/ja0664382

49. Christodoulides, D. N., I. C. Khoo, G. J. Salamo, G. I. Stegeman, and E. W. Van Stryland, "Nonlinear refraction and absorption: Mechanisms and magnitudes," Adv. Opt. Photon., Vol. 2, 60-200, 2010.
doi:10.1364/AOP.2.000060

50. Khoo, I. C., "Re-examination of the theory and experimental results of optically induced molecular reorientation and nonlinear di®ractions in nematic liquid crystals: Spatial frequency and temperature dependence," Phys. Rev., Vol. 27, 2747-2750, 1983, and References therein.
doi:10.1103/PhysRevA.27.2747

51. Khoo, I. C. and R. Normandin, "The mechanism and dynamics of transient thermal grating di®raction in nematic liquid crystal films," IEEE J. Quant. Electronics, Vol. 21, No. 4, 329-335, 1985.
doi:10.1109/JQE.1985.1072667

52. Khoo, I. C. and Y. R. Shen, "Liquid crystals-nonlinear optical properties and processes," Opt. Eng., Vol. 24, 579-585, 1985.

53. Fekete, D., J. AuYeung, and A. Yariv, "Phase conjugation reflection by degenerate four wave mixing in a nematic crystal in the isotropic phase," Optics Letters, Vol. 5, 51-53, 1980.
doi:10.1364/OL.5.000051

54. Janossy, I. and T. Kosa, "Influence of anthraquinone dyes on optical reorientation of nematic liquid crystals," Optics Letters, Vol. 17, 1183-1185, 1992.
doi:10.1364/OL.17.001183

55. Li, H., Y. Liang, and I. C. Khoo, "Transient laser induced orthogonal director axis reorientation in dye-doped liquid crystal," Mol. Cryst. Liq. Cryst., Vol. 251, 85-92, 1994.
doi:10.1080/10587259408027194

56. Yang, P., L. Liu, L. Xu, and Y. R. Shen, "Excitation-enhanced optical reorientation in nematic liquid crystals," Optics Letters, Vol. 15, 2252-2254, 2009.
doi:10.1364/OL.34.002252

57. Khoo, I. C., H. Li, and Y. Liang, "Optically induced extraordinarily large negative orientational nonlinearity in dye-doped-liquid crystal," IEEE J. Quant. Electronics, Vol. 29, No. 5, 1444-1447, 1993.
doi:10.1109/3.236160

58. Rudenko, E. V. and A. V. Sukhov, "Optically induced spatial charge separation in a nematic and the resultant orientational nonlinearity," Journal of Experimental and Theoretical Physics, Vol. 78, No. 6, 875-882, 1994.

59. Khoo, I. C., H. Li, and Y. Liang, "Observation of orientational photorefractive effects in nematic liquid crystals," Optics Letters, Vol. 19, 1723-1725, 1994.
doi:10.1364/OL.19.001723

60. Khoo, I. C., "Orientational photorefractive e®ects in nematic liquid crystal film," IEEE J. Quant. Electronics, Vol. 32, No. 3, 525-534, 1996.
doi:10.1109/3.485406

61. Khoo, I. C., "Holographic grating formation in dye- and fullerene C60-doped nematic liquid crystal film," Optics Letters, Vol. 20, 2137-2139, 1996.

62. Khoo, I. C., "Optical-DC-field induced space charge fields and photorefractive-like holographic grating formation in nematic liquid crystals," Mol. Cryst. Liq. Cryst., Vol. 282, 53-66, 1996.
doi:10.1080/10587259608037568

63. Khoo, I. C., S. Slussarenko, B. D. Guenther, and W. V. Wood, "Optically induced space charge fields, DC voltage, and extraordinarily large nonlinearity in dye-doped nematic liquid crystals," Optics Letters, Vol. 23, 253-255, 1998.
doi:10.1364/OL.23.000253

64. Lucchetti, L., M. Gentili, and F. Simoni, "Effects leading to colossal optical nonlinearity in dye-doped liquid crystals," IEEE Journal of Selected Topics in Quantum Electronics, Vol. 12, No. 3, 422-430, 2006.
doi:10.1109/JSTQE.2006.872055

65. Khoo, I. C., R. R. Michael, and P. Y. Yan, "Optically-induced molecular-reorientation in nematic liquid crystals and nonlinear optical processes in the nanosecond regime," IEEE J. Quant. Electronics, Vol. 23, No. 2, 267-272, 1987.
doi:10.1109/JQE.1987.1073318

66. Khoo, I. C. and R. Normandin, "Nanosecond laser-induced transient and erasable permanent grating diffractions and ultrasonic waves in a smectic film," J. Appl. Phys., Vol. 55, 1416-1418, 1984.
doi:10.1063/1.333234

67. Khoo, I. C. and R. Normandin, "Nanosecond degenerate optical wave mixing and ultrasonic wave generation in the nematic phase of liquid crystals," Optics Letters, Vol. 9, 285-287, 1984.
doi:10.1364/OL.9.000285

68. Khoo, I. C., R. G. Lindquist, R. R. Michael, R. J. Mansfield, and P. Lopresti, "Dynamics of picosecond laser induced density, temperature and flow-reorientation effects in the mesophases of liquid crystals," J. Appl. Phys., Vol. 69, 3853-3859, 1991.
doi:10.1063/1.348441

69. Eichler, H. J. and R. Macdonald, "Flow alignment and inertial effects in picoseconds laser-induced reorientation phenomena of nematic liquid crystals," Phys. Rev. Lett., Vol. 67, 2666-2669, 1991.
doi:10.1103/PhysRevLett.67.2666

70. Khoo, I. C. and S. Shepard, "Submillisecond grating diffractions in nematic liquid crystal films," J. Appl. Phys., Vol. 54, 5491-5493, 1983.
doi:10.1063/1.332699

71. Hrozhyk, , U. A., A. Uladzimir, S. V. Serak, N. V. Tabiryan, T. J. White, and T. J. Bunning, "Optically switchable, rapidly relaxing cholesteric liquid crystal reflectors," Optics Express, Vol. 18, 9651-9657, 2010.
doi:10.1364/OE.18.009651

72. White, T. J., R. L. Bricker, L. V. Natarajan, V. P. Tondiglia, L. Green, Q. Li, and T. J. Bunning, "Electrically switchable, photo-addressable cholesteric liquid crystal reflectors," Optics Express, Vol. 18, 173-178, 2010.
doi:10.1364/OE.18.000173

73. Khoo, I. C., J. H. Park, and J. D. Liou, "Theory and experimental studies of all-optical transmission switching in a twist-alignment dye-doped nematic liquid crystal," J. Opt. Soc. Am. B, Vol. 25, 1931-1937, 2008, and References therein.
doi:10.1364/JOSAB.25.001931

74. Khoo, I. C., J. Liou, and M. V. Stinger, "Microseconds-nanoseconds all-optical switching of visible-near infrared, 0.5 ¹m{1.55 ¹m. Lasers with dye-doped nematic liquid crystals," Mole. Cryst. Liq. Cryst., Vol. 527, 109-118, 2010.

75. Khoo, I. C., J. Liou, M. V. Stinger, and S. Zhao, "Ultrafast all-optical switching with transparent and absorptive nematic liquid crystals | implications in tunable metamaterials," Mole. Cryst. Liq. Cryst., Vol. 543, 151-159, 2011.

76. Shishido, A., O. Tsutsumi, A. Kanazawa, T. Shiono, T. Ikeda, and N. Tamai, "Rapid optical switching by means of photoinduced change in refractive index of azobenzene liquid crystals detected by re°ection-mode analysis," J. Am. Chem. Soc., Vol. 119, 7791-7796, 1997.
doi:10.1021/ja9706312

77. Khoo, I. C., A. Diaz, S. Kubo, J. Liou, M. Stinger, T. Mallouk, and J. H. Park, "Nano-dispersed organic liquid and liquid crystals for all-time-scales optical switching and tunable negative- and zero-index materials," Mole. Cryst. Liq. Cryst., Vol. 485, No. 1, 934-944, 2008.
doi:10.1080/15421400801925786

78. Hwang, J., N. Y. Ha, H. J. Chang, B. Park, and J. W. Wu, "Enhanced optical nonlinearity near the photonic bandgap edges of a cholesteric liquid crystal," Optics Letters, Vol. 29, 2644, 2004.
doi:10.1364/OL.29.002644

79. Song, L., S. Fu, Y. Liu, J. Zhou, V. G. Chigrinov, and I. C. Khoo, "Direct femtosecond pulse compression with miniature-sized Bragg cholesteric liquid crystal," Optics Letters, Vol. 38, 5040-5042, 2013.
doi:10.1364/OL.38.005040

80. Khoo, I.C., S. Webster, S. Kubo, W. J. Youngblood, J. Liou, A. Diaz, T. E. Mallouk, P. Lin, D. Peceli, L. A. Padilha, D. J. Hagan, and E. W. Van Stryland, "Synthesis and characterization of the multi-photon absorption and excited-state properties of 4-propyl 4'-butyl diphenyl acetylene," J. Mat. Chem., Vol. 19, 7525-7531, 2009.
doi:10.1039/b905716a

81. Khoo, I. C. and A. Diaz, "Multiple-time-scales dynamical studies of nonlinear transmission of pulsed lasers in a multi-photon absorbing organic material," J. Opt. Soc. Am. B, Vol. 28, 1702-1710, 2011.
doi:10.1364/JOSAB.28.001702

82. Khoo, I. C., A. Diaz, and J. Ding, "Nonlinear-absorbing fiber array for large dynamic range optical imiting application against intense short laser pulses," J. Opt. Soc. Am. B, Vol. 21, 1234-1240, 2004.
doi:10.1364/JOSAB.21.001234

83. Khoo, I. C., A. Diaz, M. V. Wood, and P. H. Chen, "Passive optical limiting of picosecond-nanosecond lasers using highly nonlinear organic liquid cored fiber array," IEEE Journal of Selected Topics in Quantum Electronics, Vol. 7, No. 5, 760-768, 2001.
doi:10.1109/2944.979336

84. Khoo, I. C., "Nonlinear organic liquid cored fiber array for all-optical switching and sensor protection against short pulsed lasers," IEEE Journal of Selected Topics in Quantum Electronics, Vol. 14, No. 3, 946-951, 2008, and References therein.
doi:10.1109/JSTQE.2008.916238

85. He, G. S., L.-S. Tan, Q. Zheng, and P. N. Prasad, "Multiphoton absorbing materials: Molecular designs, characterizations, and applications," Chemical Reviews, Vol. 108, No. 3, 1245{-1330, 2008, and References therein.
doi:10.1021/cr050054x

86. Takanashi, H., J. E. Maclennan, and N. A. Clark, "Sub 100 nanosecond pretilted planar-to-homeotropic reorientation of nematic liquid crystals under high electric field," Jpn. J. Appl. Phys., Vol. 37, No. 5, 2587-2589, 1998.
doi:10.1143/JJAP.37.2587

87. Geis, M. W., R. J. Molnar, G. W. Turner, T. M. Lyszczarz, R. M. Osgood, and B. R. Kimball, "30 to 50 ns liquid-crystal optical switches," Proc. SPIE, Vol. 7618, 76180J-1-76180J-5, 2010.

88. Pawlik, G., K. Tarnowski, W. Walasik, A. C. Mitus, and I. C. Khoo, "Infrared cylindrical cloak in nanosphere dispersed liquid crystal metamaterial," Optics Letters, Vol. 37, 1847-1849, 2012.
doi:10.1364/OL.37.001847

89. Pawlik, G., G. Pawlik, W. Walasik, K. Tarnowski, A. C. Mitus, and I. C. Khoo, "Liquid crystal hyperbolic metamaterial for wide-angle negative-positive refraction and reflection," Optics Letters, Vol. 39, 1744-1747, 2014.
doi:10.1364/OL.39.001744

90. Jarema, M., W. Walasik, A. C. Mitus, and I. C. Khoo, "Field induced inhomogeneous index distribution of a nano-dispersed nematic liquid crystal near the Freedericksz transition: Monte carlo studies," J. Opt. Soc. Am. B, Vol. 27, No. 3, 567-576, 2010.
doi:10.1364/JOSAB.27.000567

91. Pawlik, G., W. Walasik, A. C. Mitus, and I. C. Khoo, "Large gradients of refractive index in nanosphere dispersed liquid crystal metamaterial with inhomogeneous anchoring: Monte Carlo study," Optical Materials, Vol. 33, No. 9, 1459-1463, 2011.
doi:10.1016/j.optmat.2011.02.005

92. Khoo, I. C. and T. H. Lin, "Nonlinear optical grating diffraction in dye-doped blue-phase liquid crystals," Optics Letters, Vol. 37, 3225-3227, 2012.
doi:10.1364/OL.37.003225

93. Chen, C.-W., H.-C. Jau, C.-T. Wang, C.-H. Lee, I. C. Khoo, and T.-H. Lin, "Random lasing in blue phase liquid crystals," Optics Express, Vol. 20, No. 21, 23978-23984, 2012.
doi:10.1364/OE.20.023978

94. Khoo, I. C., K. L. Hong, S. Zhao, D. Ma, and T.-H. Lin, "Blue-phase liquid crystal cored optical fiber array with photonic bandgaps and nonlinear transmission properties," Optics Express, Vol. 21, No. 4, 4319-4327, 2013.
doi:10.1364/OE.21.004319

95. Chen, C. W., H. C. Jau, C. H. Lee, C. C. Li, C. T. Hou, C. W. Wu, T. H. Lin, and I. C. Khoo, "Temperature dependence of refractive index in blue phase liquid crystals," Optical Materials Express, Vol. 3, No. 5, 527-532, 2013.
doi:10.1364/OME.3.000527

96. Kikuchi, H., M. Yokota, Y. Hiskado, H. Yang, and T. Kajiyama, "Polymer-stabilized liquid crystal blue phases," Nat. Mater., Vol. 1, 64-68, 2002.
doi:10.1038/nmat712

97. Coles, H. and M. N. Pivnenko, "Liquid crystal `blue phases' with a wide temperature range," Nature, Vol. 436, 997-1000, 2005.
doi:10.1038/nature03932

98. Hisakado, Y., H. Kikuchi, T. Nagamura, and T. Kajiyama, "Large electro-optic Kerr effect in polymer-stabilized liquid-crystalline blue phases," Adv. Mater., Vol. 17, 96, 2005.
doi:10.1002/adma.200400639

99. Ge, Z., S. Gauza, M. Jiao, H. Xianyu, and S.-T. Wu, "Electro-optics of polymer-stabilized blue phase liquid crystal displays," Appl. Phys. Lett., Vol. 94, 101104, 2009.
doi:10.1063/1.3097355