Holographic Polymer Nanocomposites with High Refractive Index Modulation by Doping Liquid Crystal E6M

Abstract

Holographic optical elements (HOEs) based on polymer composites have become a research hot spot in recent years for augmented reality (AR) due to the significant improvement of optical performance, dynamic range, ease of processing and high yield rate. Nevertheless, it remains a formidable challenge to obtain a large field of view (FOV) and brightness due to the limited refractive index modulation. Herein, we report an effective method to tackle the challenge by doping an epoxy liquid crystal termed E6M, which enables a large refractive index modulation of 0.050 @ 633 nm and low haze of 5.0% at a doping concentration of 5 wt%. This achievement may be ascribed to the improved molecular ordering of liquid crystals within the holographic polymer composites. The high refractive index modulation can endow transmission-type holographic polymer composites with a high diffraction efficiency of 96.2% at a small thickness of 5 µm, which would promise the design of thin and lightweight AR devices.