Tunable 2-mm lasing in calcium – niobium – gallium garnet crystals doped with Ho3+ ions

Lasing on the ⁵I₇ → ⁵I₈ transition of Ho³⁺ ions in holmium-doped calcium – niobium – gallium garnet crystals is obtained at a wavelength of about 2095 nm with an output power of 2.1 W under pumping by a laser based on Tm : LiYF₄ crystal. Tunable lasing in these crystals within a wavelength range of 2045–2120 nm is achieved using an interference – polarisation filter.