Electrically tunable selective reflection of light from ultraviolet to visible and infrared by heliconical cholesterics

TL;DR

This paper demonstrates that heliconical cholesteric liquid crystals can be electrically tuned to selectively reflect a broad spectrum of light from ultraviolet to infrared, enabling versatile dynamic optical applications.

Contribution

It introduces a novel use of heliconical cholesteric structures for broad spectral tuning of reflected light via electric fields, expanding potential applications.

Findings

Wavelength of reflected light can be tuned from 360 to 1520 nm.

The effect is stable across a wide temperature range, including room temperature.

Potential applications include smart windows, tunable lasers, and displays.

Abstract

Cholesteric liquid crystals with helicoidal molecular architecture are known for their ability to selectively reflect light with the wavelength that is determined by the periodicity of molecular orientations. Here we demonstrate that by using a cholesteric with oblique helicoidal(heliconical) structure, as opposed to the classic right-angle helicoid, one can vary the wavelength of selectively reflected light in a broad spectral range, from ultraviolet to visible and infrared (360-1520 nm for the same chemical composition) by simply adjusting the electric field applied parallel to the helicoidal axis. The effect exists in a wide temperature range (including the room temperatures) and thus can enable many applications that require dynamically controlled transmission and reflection of electromagnetic waves, from energy-saving smart windows to tunable organic lasers, reflective color display, and transparent see-through displays.