Using a mode-locking Nd:YAG laser, we measured the second harmonic generation (SHG) of polymer stabilized cholesteric texture (PSCT) films. SHG observed in these samples is due to the dielectric gradient which arises from the interfaces between the cholesteric liquid crystal/polymer and those between the adjacent cholesteric focal conic domains having different helical axis. Both of the SHG intensities and the electro-optical characteristics of PSCTs were measured as a function of polymer concentration. In addition, polymer network structures formed in PSCTs were investigated. Good correlations among the SHG measurements, electro-optical characteristics, and the polymer network morphologies were found. It means that SHG measurements could provide us another qualitative, nondestructive method to analyze the PSCT films. In addition, SHG change on polymerization can be used to monitor the polymerization of LC-polymer mixtures.

Date Published: 14 October 1998
PDF: 10 pages
Proc. SPIE 3475, Liquid Crystals II, (14 October 1998); doi: 10.1117/12.326892

Published in SPIE Proceedings Vol. 3475:
Liquid Crystals II
Iam-Choon Khoo, Editor(s)