Three-Dimensional Waveguide Splitters Inscribed in Nd:YAG by Femtosecond Laser Writing: Realization and Laser Emission

In this paper, we report on a three-dimensional beam splitter monolithically integrated in an Nd:YAG laser crystal wafer by applying the direct femtosecond laser writing technique with the photonic-lattice-like cladding approach, capable of 1 to 2 and 1 to 4 beam splitting. Using the pump at 808 nm, 1064-nm splitting lasers with slope efficiencies of 34% and 22% for 1 to 2 and 1 to 4 configurations were realized. This study paves a way to fabricate direct-pump compact laser devices in a single chip for light guiding and beam dividing in Nd:YAG crystals for various photonic applications.