On the thermal stability of volume holograms recorded in nanoparticle-polymer composite films

Abstract

We report on measurements of thermal expansion coefficients and temperature-dependent refractive indices of nanoparticle-polymer composite films in which plane-wave volume holograms are recorded. These physical constants are evaluated for photopolymer films with the incorporation of inorganic nanoparticles or binder polymer. We show that the incorporation of inorganic nanoparticles in photopolymer is a very effective method to suppress temperature-dependent film-thickness and refractive-index changes as well as to increase the refractive index modulation and reduce polymerization shrinkage.