Lasing characteristics of ZrO2 – Y2O3 – Ho2O3 crystal

The spectral dependences of the gain cross section of the ⁵I₈ → ⁵I₇, ⁵I₇ → ⁵I₈ transition of Ho³⁺ ions in the ZrO₂ – 13.6 mol % Y₂O₃ – 0.4 mol % Ho₂O₃ crystal are calculated at different relative population inversions using the absorption and luminescence spectra of the ⁵I₈ → ⁵I₇ and ⁵I₇ → ⁵I₈ transitions of Ho³⁺ ions at T = 300 K. Lasing of these crystals at the ⁵I₇ → ⁵I₈ transition is obtained for the first time under pumping by a Tm : YLiF₄ laser (λ_p = 1.905 μm). The lasing wavelength is 2.17 μm.