Optical-lattice-like waveguide structures in Ti:Sapphire by femtosecond laser inscription for beam splitting

Abstract

In this work, we report on the fabrication of deeply embedded optical-lattice-like structures in a Ti:Sapphire crystal by applying femtosecond laser inscription (FLI) to implement two-dimensional (2D) one-to-two and three-dimensional (3D) one-to-four beam splitting. Such a family of photonic microstructures is characterized at near-infrared both experimentally and numerically, showing excellent capability of simultaneous light confinement and beam tailoring at two orthogonal polarizations. The confocal micro-Raman image of the obtained structure reveals that the optical properties of the substrate have been well-preserved in the waveguide’s active volumes. Our results pave a way to construct complex integrated waveguide splitters in Ti:Sapphire crystals by using FLI for photonic applications.