Accession Number : ADA622529


Title :   Low-Absorption Liquid Crystals for Infrared Beam Steering


Descriptive Note : Final rept. 23 Oct 2012-30 Sep 2015


Corporate Author : UNIVERSITY OF CENTRAL FLORIDA ORLANDO


Personal Author(s) : Wu, Shin-Tson


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a622529.pdf


Report Date : 30 Sep 2015


Pagination or Media Count : 40


Abstract : 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.


Descriptors :   *LIQUID CRYSTALS , ABSORPTION , BEAM STEERING , EUTECTICS , LIGHT MODULATORS


Subject Categories : Physical Chemistry


Distribution Statement : APPROVED FOR PUBLIC RELEASE