Direct writing of functional ferroelectric waveguides in glass

Femtosecond lasers modify the refractive index of many transparent materials for writing high quality waveguides due to their ability to confine the optical damage to an intended region [1]. They also can precipitate microcrystalline structures in glass and have demonstrated the production of ferroelectric crystals that can be used for optical waveguiding [2,3]. Ferroelectric crystals such as lithium niobate are some of the most widely used optical materials due to their strong electro-optic, piezoelectric, and photorefractive properties. The structure and alignment of the precipitated ferroelectric crystals can be controlled through the incident beam profile, writing speed and the starting material composition[2]. In this study crystalline waveguide structures were be written in 33LiO$_{\mathrm{2}}$-33Nb2O$_{\mathrm{5}}$-34SiO$_{\mathrm{2}}$ (mol{\%}) glass, characterized, the structural orientation determined, and their waveguiding performance tested. This procedure was then modified to functionalize the precipitated waveguides for photonic and holographic applications. [1] C. Mauclair et al., Opt. Exp. 16, (2008). [2] A. Stone et al., Sci. Reports \textbf{5}, 10391 (2015). [3] T. Komatsu et al., J. Sol. State Chem. 184, 411 (2011).