Volume hologram formation in liquid-crystal/photopolymer mixtures

摘要

We present a study of the real-time formation of volume holographic reflection gratings in a liquid-crystal/photopolymer mixture. The diffraction efficiency for s- and p-polarization, Bragg wavelength, and laser scattering are monitored as the grating is formed. We present a model of grating formation that incorporates the photophysics of the initiator dye, reaction-diffusion equations of the monomer-polymer-liquid crystal system, phase separation of the liquid crystal, nematic order evolution, and volume shrinkage of the polymer. The model yields good qualitative agreement with experimental data. We discuss the physics of the system as it evolves in time and describe the effects of various phenomena on the diffraction efficiency of holographic polymer-dispersed liquid crystal gratings.