Ho3+/Tm3+ codoped lead silicate glass for 2 μm laser materials

The mid-infrared emission of low phonon (963 cm^-1) lead silicate glass system with Ho³⁺/Tm³⁺ co-doped has been investigated. Luminescence at ∼2.1 μm corresponding to ⁵I₇ → ⁵I₈ transition in holmium was obtained by energy transfer between Tm³⁺ and Ho³⁺ ions. Energy transfer mechanism between them was analyzed. And the highest value of the luminescence intensity was obtained in glass co-doped with 1Tm₂O₃/0.3Ho₂O₃. The full width at half maximum of the (Ho³⁺/Tm³⁺) emission reached to 350 nm in 1Tm₂O₃/0.1Ho₂O₃ sample. Absorption and emission cross section have also been calculated and analyzed. The maximum emission cross section was 3.9 × 10^-21 cm² around 2.0 μm. And when P > 0.4, a positive gain can be obtained at wavelengths >1941 nm. Results demonstrated that the prepared Ho³⁺/Tm³⁺ co-doped lead silicate glasses have excellent spectroscopic properties in mid-infrared wavelengths and can obtain high gain in fiber lasers.