Nd³⁺-Doped La₂CaB₈O₁₆Crystals for Orthogonally Polarized Dual-Wavelength Near-Infrared Lasers

The Nd3+-based laser crystal is one of the key gain media for all-solid-state laser technology. Herein, by investigating the relationship between structure and optical properties, we found that a La-containing borate, La2CaB8O16, with a long rare-earth ion distance more than 4.27 Å, allows a high doping concentration and exhibits a weak fluorescence quenching effect. For the first time, Nd3+-doped La2CaB8O16 crystals with different concentrations were grown by the top seeded solution growth method with large size and high optical quality. Its spectral characters were measured, suggesting a strong absorption band at 800 nm and a fluorescence band at 1055 nm. Furthermore, a diode-pumped orthogonally polarized dual-wavelength laser operation at 1052 and 1055 nm was realized, with a slope efficiency of 16.3% and output power of 859 mW. These results suggest that the Nd3+-doped La2CaB8O16 crystal is a promising laser gain medium for 1 μm lasers and possible generation of terahertz radiation.