The formation and characterization of optical waveguide in Nd:YLF crystal by 4.5-MeV Si ion implantation

Highlights: • In present work, we report the active optical waveguides in Nd:YLF crystals fabricated by 4.5 MeV Si ions implantation at room temperature. • According to the studies, the prism-coupling and RCM calculations results show that the guiding mode can be well confined by the waveguide structures. • The spectral results demonstrate the initial upconversion luminescence intensity of Nd³⁺ ions can be effectively improved after irradiation at fluences of 1.0× 10¹⁴ cm^-2. -- Abstract: The planar waveguides have been fabricated in Nd:YLF crystals by Si implantation. The guiding properties of Si-implanted waveguide are evaluated by the prism-coupling technique and reflectivity calculation method (RCM), exhibiting good confinement and monomode behavior at 632.8 nm. The investigation of the photoluminescence (PL) measurement demonstrates that the luminescence characteristics of the Nd³⁺ ions are not significantly altered by the Si ions irradiation process, whereas the up-conversion (UC) luminescence intensity can be effectively improved. Based on the pump-power-dependent fluorescence, the possible emission mechanism in Nd:YLF is proposed.