Abstract: Mid-infrared laser crystals operating in the 2.1 µm spectral region are widely utilized in eye-safe applications, remote sensing, and medical surgery. In this study, we successfully grew high-quality 2.5% Tm:YScO₃ single crystals (2.5% is in atomic) using the Czochralski method. We systematically characterized their room-temperature absorption and fluorescence spectra, measured fluorescence lifetimes, calculated key spectroscopic parameters based on Judd-Ofelt theory, and evaluated their continuous-wave (CW) laser performance. The results indicate that the crystal exhibits an absorption cross-section of 0.33×10^-20 cm² at 794 nm with a full width at half maximum (FWHM) of 23.5 nm. The Judd-Ofelt intensity parameters Ω₂, Ω₄, and Ω₆ were determined to be 2.55×10^-20, 0.80×10^-20, and 0.66×10^-20 cm², respectively, yielding a calculated radiative lifetime of 6.52 ms for the ³F₄ level. Furthermore, the emission cross-section at 1960 nm was found to be 0.44×10^-20 cm² with a broad FWHM of 86.63 nm, while the measured fluorescence lifetime was 3.855 ms. Under an incident pump power of 20 W, the laser achieved a maximum output power of 2.78 W with a slope efficiency of 22.66% and excellent beam quality factors of M_x²=1.12 and M_y²=1.09. The combination of a broad emission bandwidth and superior beam quality suggests that Tm:YScO₃ is particularly well-suited for tunable and ultrafast laser applications. In conclusion, the 2.5% Tm:YScO₃ crystal grown by the Czochralski method demonstrates exceptional spectroscopic and lasing properties, establishing it as a highly promising candidate for next-generation 2.1 µm solid-state laser systems.

Key words: Czochralski method, Tm:YScO₃, crystal growth, spectroscopic properties, laser performance