Low-Absorption Liquid Crystals for Infrared Beam Steering
Final rept. 23 Oct 2012-30 Sep 2015
UNIVERSITY OF CENTRAL FLORIDA ORLANDO
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The objective of this project is to develop high birefringence, large dielectric anisotropy, and low optical loss nematic liquid crystals for infrared laser beam steering applications. To suppress the optical loss in MW1R and LW1R, we have investigated following approaches 1 Employing a thin cell gap 2 Red-shifting the absorption bands to outside the spectral region of interest by deuteration, fluorination, or chlorination 3 Reducing the overtone absorption by using a short alkyl chain. We have synthesized several fluorinated and chlorinated terphenyl compounds and formulated a eutectic mixture showing high birefringence and low absorption over 98 transmittance in the MW1R region, while possessing a modest positive dielectric anisotropy and wide nematic range. To achieve fast response time, we developed a polymer network liquid crystal with 2-pi phase change at MW1R and response time less than 4ms. To extend the potential applications into LWIR, we synthesized several chlorinated teiphenyl compounds with high birefringence and an aromatic ring-deuterated cyano-biphenyl compound to achieve high transmittance.
- Physical Chemistry