Growth, spectroscopic features and efficient 2 μm continuous-wave laser output of a Tm3+: Gd0.1Y0.9AlO3 disordered crystal

Abstract

Tm3+-doped Gd0.1Y0.9AlO3 (GYAP) disordered crystal with size of Φ (28–35) mm × (50–70) mm was grown successfully by the Czochralski method. The X-ray powder diffraction, polarized absorption spectra, and polarized luminescence spectra of Tm3+: GYAP crystal were measured to investigate the structural and luminescent properties of the crystal. The cell parameters of Tm3+: GYAP crystal were found to be a = 5.321 Å, b = 7.371 Å, and c = 5.176 Å, respectively. The spectral parameters such as line strengths, Judd-Ofelt (J-O) intensity parameters Ω2,4,6, the radiative transition rates, the branching ratios, and the radiative lifetimes were calculated based on the J-O theory. The absorption cross-sections were determined to be 0.47 × 10−20 cm2 (at 797 nm), 0.55 × 10−20 cm2 (at 777 nm), and 0.41 × 10−20 cm2 (at 794 nm), respectively. The Tm3+: GYAP crystal, as far as we know, was firstly used for laser demonstration with a 793 nm laser diode (LD). The slope efficiency up to 6.4% was achieved with maximum output power of 426 mW at 1941.953 nm. The resulting linear polarized and stable laser output indicate that the Tm3+: GYAP disordered crystal can be applied to achieving tunable and ultra-short laser at ~2 μm.