Crystal growth and properties characterization of Nd3+:Na5Lu(MoO4)4 for continuous multi-wavelength NIR laser emission

Abstract

A new Nd³⁺ ions-doped NIR laser crystal of Na₅Lu(MoO₄)₄ was grown in a 4Na₂O–5MoO₃ flux through the top-seeded solution growth (TSSG) technique. Thermal analysis indicated that Na₅Lu(MoO₄)₄ melted incongruently and decomposed at 690 °C into NaLu(MoO₄)₂ and Na₂MoO₄. The photoluminescence measurements for different Nd³⁺ dopant concentrations showed that Na₅Lu(MoO₄)₄ can achieve high activator doping, and the saturation concentration for Nd³⁺ ions can reach 10% without an obvious quenching effect. In addition, the optical absorption spectra for the 1.48% Nd³⁺:Na₅Lu(MoO₄)₄ single crystal were measured, from which the absorption parameters of Ω₂ = 5.288 × 10⁻²⁰ cm², Ω₄ = 3.802 × 10⁻²⁰ cm², and Ω₆ = 5.206 × 10⁻²⁰ cm² were calculated by the Judd–Ofelt theory. Furthermore, a continuous multi-wavelength NIR laser emission with a 60 mW laser power around 1059 nm and 1065 nm multi-bands and slope efficiency of 6.2% output was achieved in the Nd³⁺:Na₅Lu(MoO₄)₄ crystal for the first time, showing promising applications as a new kind of laser diode (LD) pumped ultrashort pulse solid-state laser.