Microstructure and optical properties of tracks with precipitated silver nanoparticles and clusters inscribed by the laser irradiation in phosphate glass

Abstract

Direct laser writing (DLW) in transparent dielectric hosts such as oxide glasses allows 3D micro-and nano-modification of materials structure and properties. One of the most prominent applications of DLW in glasses for photonics is the inscription of optical waveguides based on local refractive index change (Δn). According to the parameters of the DLW, three types (type I, type II & type III) of modifications are usually distinguished in glasses. Moreover, in silver-containing glasses, it is possible to induce type A modification which is based on the refractive index change due to silver clusters precipitation. In this work, we report on the DLW of an additional type of modification related to type A one and based on the simultaneous precipitation of plasmonic silver nanoparticles and clusters and therefore propose a more precise classification of the glass microstructure modification: type AC for only silver clusters precipitation and type AN for both silver nanoparticles and clusters. We studied the dependence of the microstructure of laser-inscribed tracks in glass on the laser exposure parameters and showed that by tuning the latter, it is possible to induce various types of microstructure modification and to write tracks with different optical properties.