Reflection holographic photopolymer gratings with an anharmonic modulation of the refractive index

Abstract

The subject is reflection holographic photopolymer gratings with an anharmonic profile of the refractive index modulation. The goal of this work is to determine the conditions for the formation of a holographic photopolymer material synthesized at the N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, volume reflection holograms with a high diffraction efficiency in the first and second diffraction orders, as well as their characterization, a calculation of the refractive index modulation in the first and second orders of diffraction, a determination of the dependence of the diffraction efficiency on the type of polymer binder, as well as irradiated intensity. Method. The characterization of the obtained holograms included recording the formed holograms’ transmission spectra, theoretical evaluation of their diffraction efficiency, and refractive index modulation amplitude using known formulas. Results. The diffraction and spectral properties of holographic photopolymer gratings with a high anharmonic modulation of the refractive index modulation are studied. Samples of the reflection gratings with a second-order diffraction efficiency of 90% were obtained. The dependence of these properties on the type of polymer matrices (polyvinyl acetate, polyurethane) and the intensity of the incident radiation is established. Practical significance. The high efficiency of the diffraction second order in reflection photopolymer holograms can be useful for creating additional properties of security elements.