Electrically tunable total reflection of light by oblique helicoidal cholesteric

TL;DR

This paper demonstrates that oblique helicoidal cholesteric liquid crystals can achieve electrically tunable total reflection of light across a broad spectrum, with potential applications in optical devices.

Contribution

It introduces a novel electrically tunable total reflection phenomenon in oblique helicoidal cholesteric liquid crystals, expanding their functional capabilities.

Findings

Oblique helicoidal cholesteric reflects 100% of incident light at oblique angles.

Multiple reflection bands (P/2, P/3, P/4) can be electrically tuned.

Broad spectral tuning from ultraviolet to infrared achieved.

Abstract

An oblique helicoidal state of a cholesteric liquid crystal (ChOH) is capable of continuous change of the pitch P in response to an applied electric field. Such a structure reflects 50% of the unpolarized light incident along the ChOH axis in the electrically tunable band determined by P/2. Here we demonstrate that at an oblique incidence of light, ChOH reflects 100% of light of any polarization. This singlet band of total reflection is associated with the full pitch P. We also describe the satellite P/2, P/3, and P/4 bands. The P/2 and P/4 bands are triplets while P/3 band is a singlet caused by multiple scatterings at P and P/2. A single ChOH cell acted upon by an electric field tunes all these bands in a very broad spectral range, from ultraviolet to infrared and beyond, thus representing a structural color device with enormous potential for optical and photonic applications.