Polymer dispersed nematic liquid crystal films with conical boundary conditions for electrically controllable polarizers

Krakhalev, Mikhail N.; Prishchepa, Oxana O.; Sutormin, Vitaly S.; Zyryanov, Victor Ya Source: OPTICAL MATERIALS, 89 1-4; 10.1016/j.optmat.2019.01.004 MAR 2019

Polymer dispersed nematic liquid crystal (PDNLC) films with conical boundary conditions at the LC-polymer interface are considered. The conical surface anchoring with tilt angle 40^° initiates forming the axial-bipolar director configuration inside nematic droplets. This droplet structure exhibits the strong scattering of light polarized parallel to the bipolar axis. In the initial state, the bipolar axes in all droplets are oriented randomly, and therefore PDNLC film scatters a light of any polarization. Electric field applied along the film plane orients the bipolar axes unidirectionally in the whole droplet ensemble, that results in its high polarization-dependent transmittance. Such PDNLC films can be used in the electrically controllable linear polarizers characterized by 89% value of the transmittance for the perpendicular polarized light and high extinction ratio 590:1 at the electric field 0.34 V/μm.