LC dependent electro-optical properties of holographic polymer dispersed liquid crystals

Holographic polymer dispersed liquid crystals (HPDLC) have been fabricated from four different types of LC at a specific resin composition to optimize the electro-optical performance of the film. Among them, ZLI-3417-100 gave the lowest driving voltage (<2.5 V/μm) and fastest response time (<10 ms) which was interpreted in terms of high dielectric anisotropy (Δɛ) and low viscosity of the LC. However, diffraction efficiency of the film was a bit low due to the relatively small refractive anisotropy (Δn) of the LC giving rise to a small mismatch of refractive index with resin. With regard to the LC content, 40% LC gave the greatest diffraction efficiency, whereas saturation time decreased with increasing content of LC, which emphasizes the viscosity reducing effect of LC.