The Research On Optical Storage Characteristics Of Ag/TiO₂ Nanocomposite Films Based On Surface Plasmon Resonance Absorption Of Ag Nanoparticles

Noble metal nanoparticles has been recognized as one of the promising nanomaterials with various applications such as, chemical sensors, biological sensors, and photonic circuits, due to their unique surface plasmon resonance absorption properties. Recently, studies showed that a nanoporous TiO₂ film loaded with Ag nanoparticles exhibits interesting multicolor photochromism. This novel photochromic material may have potential applications in various fields such as optical data storage, drawing materials, colorimetric sensors, optical filters, smart glass, and display devices and so on. Herein we have systematic investigated the holographic data storage properties of photochromism Ag/TiO₂ nanocomposite films, and discuss the mechanism of forming/ erasing holographic gratings on the Ag/TiO₂ nanocomposite films, as well as the stability of the holographic fringes.The experimental results showed that holographic grating were observed to form gradually on the Ag/TiO₂ nanocomposite film using two coherent green laser beams (532 nm) as writing beams and a red laser beam (633 nm) as a probe beam. The holographic gratings could be erased with ultraviolet irradiation, and recovered again with two coherent green laser beams. The saturated value of the diffraction efficiency increaseed with the intensities of writing beams within a certain range. The holographic fringes exhibited good longevity in dark environment. Modification of the Ag nanoparticles with dodecanethiol would improve the stability of the holographic fringes. We further analyzed and discussed the interaction or interfacial charge transfer between silver nanoparticles and TiO₂ film under light- stimulated condition. It was shown that holographic data storage properties of Ag/TiO₂ nanocomposite films were consistent with the photochromism and can be well explained by the visible light- stimulated dissolution and ultraviolet light-stimulated regeneration of silver nanoparticles in TiO₂ matrix.