Electrically tunable structural colors of cholesterics with oblique helicoidal director
Abstract
A cholesteric liquid crystal was recently shown to exhibit a peculiar oblique helicoidal state (ChOH) when acted upon by an electric field. The period of ChOH structure depends strongly on the applied field, which enables electrically tunable structural colors in an extraordinary broad spectral range from ultraviolet to infrared. We present experimental and theoretical studies of light reflection from ChOH as a function of the electric field, surface anchoring, and incident angle. Unlike the case of conventional cholecterics, ChOH shows tunable reflection at periodicities that correspond to both pitch (for oblique incidence) and half-the-pitch. Reflection spectra are used for the first in-situ measurements of bend elastic constant of the chiral material.
The work was supported by NSF Grant DMR-1410378 and REU program CHE-1659571.- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- 2019
- Bibcode:
- 2019APS..MARC50011I