Proceedings Article | 2 November 2016
KEYWORDS: Liquid crystals, Phase shift keying, Electro optics, Modulation, Birefringence, Switches, Temperature metrology, Molecules, Telecommunications, Kerr effect
The first reported SmAPF phase, formed from the bent core mesogen W586, exhibits interesting and useful electrooptics.(1) Specifically, in teflon-aligned cells, upon application of an electric field, modulation of the birefringence is observed without rotation of the apparent optic axis. In addition, optical latching is observed, providing the long sought but never before seen “infinitely multistable" ferroelectric LC electrooptic switch.
Based upon careful measurements of the cell behavior, the polar order parameter at temperatures just above the transition to a lower-lying smectic phase is close to unity. This suggested potential application of the phase as a host for controlled polar alignment of guest molecules.
One clear application of the system is for electronic electrooptic modulation of light at telecommunications wavelengths (Kerr effect), which can be obtained in materials with polar orientation of visible dyes.
Background and results of recent experiments in the host-guest chemistry of the W586 SmAPF phase, showing good orientation of designed NLO dyes, will be presented.
(1) a) Reddy, R. A.; Zhu, C.; Shao, R.; Korblova, E.; Gong, T.; Shen, Y.; Garcia, E.; Glaser, M. A.; Maclennan, J. E.; Walba, D. M.; Clark, N. A. "Spontaneous ferroelectric order in a bent-core smectic liquid crystal of fluid orthorhombic layers," Science 2011, 332, 72-77. b) Korblova, E.; Walba, D.; Gong, T.; Reddy, A.; Zhu, C.; Shao, R.; Maclennan, J.; Glaser, M.; Clark, N. "Design and synthesis of an achiral ferroelectric smectic liquid crystal," Proc. SPIE 2011, 8114, (1), 81140X-1 - 81140X-9.
(2) United States Patent: Walba US 9,187,500 B2, Nov. 17, 2015
