Polarized spectral analysis of Ho3+ions in biaxial YAlO3crystal for 2 µm lasers

An Ho 3+ -doped YAlO 3 (Ho : YAP) single crystal has been grown by the Czochralski technique. The polarized absorption spectra, polarized fluorescence spectra and fluorescence decay curve of the crystal are measured at room temperature. The spectroscopic parameters are calculated based on Judd–Ofelt theory, and the effective phenomenological intensity parameters Ω 2,eff , Ω 4,eff and Ω 6,eff are obtained to be 2.89 × 10 −20 , 2.92 × 10 −20 and 1.32 × 10 −20 cm 2 , respectively. The room-temperature fluorescence lifetime of the Ho 3+ 5 I 7 → 5 I 8 transition is measured to be 8.1 ms. Values of the absorption and emission cross-sections with different polarizations are presented for the 5 I 7 manifold, and the polarized gain cross-section curves are also provided and discussed.