High contrast chiral nematic liquid crystal device using negative dielectric material

A liquid crystal device is demonstrated using a short-pitch (260 nm) chiral nematic with negative dielectric anisotropy. Due to dielectric coupling, an in-plane electric field switches the liquid crystal between the standing-helix (field-off, “dark” state) and lying-helix (field-on, transmissive state) configurations. We report experimental results on the optical transmission as a function of the applied field, the response time (as short as 35 microseconds) and the contrast ratio (1000:1).