Growth, spectroscopy and CW laser operation of Ho3+ doped CaY0.9Gd0.1AlO4 single crystal

Ho3+-doped CaY0.9Gd0.1AlO4 single crystal was successfully grown by the Czochralski technique for the first time. The polarized absorption spectra, polarized luminescence spectra and fluorescence decay curve of the crystal were investigated at room temperature. The spectroscopic parameters are calculated based on Judd–Ofelt theory, the values of Ω2,4,6 were calculated to be 3.16 × 10−20 cm2, 3.93 × 10−20 cm2, 0.91 × 10−20 cm2, respectively. The Ho:CaY0.9Gd0.1AlO4 crystal exhibits strong emission at 2013 nm for π- and 2032 nm for σ-polarizations with stimulated emission cross section of 6.64 × 10−20 cm2 and 1.90 × 10−20 cm2, respectively. The fluorescence lifetime of the 5I7 level was measured to be 6.60 ms. The continuous-wave (CW) laser operation of Ho:CaY0.9Gd0.1AlO4 crystal around 2 μm was demonstrated.