Studies of second harmonic generation in liquid crystal-polymer mixtures

Andy Ying Guey Fuh, Chi Yen Huang, Cheuk Wah Lau, Liang Chy Chien

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Abstract

Films of liquid crystal (LC)-polymer dispersion materials having various chiral dopant and monomer concentrations were fabricated. Using a mode-locking Nd:YAG laser, we observed second harmonic generation (SHG) in these mixtures which is due to the dielectric gradient across the interfaces between the LC/polymer network and those between adjacent cholesteric domains having a different helical axis. The results showed that UV curing intensity, polarization of incident light and frequency of driving voltage affected SHG intensity significantly. Chiral dopant concentration was also found to affect not only the threshold voltage, but the SHG intensity of the cell. Finally, two experiments that highlighted the applications of SHG measurements in LC-polymer mixtures were conducted. Polarization-dependent SHG measurement can be used to determine the dielectric constant of the polymer dispersed in LC cells, and SHG change on polymerization can be used to monitor the polymerization of LC-polymer mixtures.

Original languageEnglish
Pages (from-to)6832-6838
Number of pages7
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume36
Issue number11
Publication statusPublished - 1997 Nov 1

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All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

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