Fabrication of multi-pitched photonic structure in cholesteric liquid crystals based on a polymer template with helical structure

Abstract

In this study, we demonstrate a novel method for fabricating a single-layer Ch-LC film with multi-pitched photonic structure as new photonic band gap (PBG) materials by utilizing a polymer template. The polymer template with helical structure was originated from polymer-stabilized cholesteric liquid crystals. Various types of Ch-LCs are subsequently imbibed into the polymer template, resulting in films with distinct optical characteristics. Simultaneous red, green and blue reflection (multiple PBGs) and wide-band reflection in a single-layer Ch-LC film can be achieved by using nematic liquid crystals with different birefringence in Ch-LCs/polymer template composites, and a H-bonded Ch-LC with a great temperature-dependence of pitch length was introduced into the polymer template, and a temperature-tunable PBG of the Ch-LC film with a double-handed circularly polarized light reflection band was obtained. Additionally, the lasing emission of a single-layer Ch-LC film and patterning of a single-layer Ch-LC film with a double-handed circularly polarized light reflection band were also realized by the above approach. These special optical properties make the novel Ch-LCs composites interesting for their great potential applications in many fields, such as information recording, optical components, flat displays, photonic crystals etc.