Holographic Polymer Dispersed Liquid Crystal Mixtures with High Diffraction Efficiency and Low Haze

A holographic polymer dispersed liquid crystal formulation, comprising:

• monomers;
• photoinitiators;
• and
• a liquid crystal mixture comprising higher-index liquid crystal compounds having an ordinary refractive index at 550 nm and at 25 degrees Celsius of 1.7 or more and other liquid crystal compounds having an ordinary refractive index at 550 nm and at 25 degrees Celsius of less than 1.7, said liquid crystal mixture having a ratio of at least 1:10 by weight percentage of said higher-index liquid crystal compounds to said other liquid crystal compounds;
• wherein said photoinitiators is configured to facilitate a photopolymerization induced phase separation process of said monomers and said liquid crystal mixture.

A method for forming a holographic optical element, the method comprising:

• providing a first transparent substrate;
• depositing a layer of optical recording material onto said first substrate, wherein said layer of optical recording material comprises a liquid crystal mixture comprising terphenyl compounds and non-terphenyl compounds, said liquid crystal mixture having a ratio of at least 1:10 by weight percentage of said terphenyl compounds to said non-terphenyl compounds;
• placing a second transparent substrate onto said deposited layer of optical recording material;
• exposing said layer of optical recording material using at least one recording beam;
• and
• forming a waveguide having at least one grating structure within said layer of optical recording material.