Dual effects of Nd³⁺ in Nd³⁺/Ho³⁺:CaLaGa₃O₇ crystal on 2.86 µm emission

Enhanced 2.86 µm emission corresponding to Ho³⁺: ⁵I₆→⁵I₇ was achieved in Nd³⁺/Ho³⁺ codoped CaLaGa₃O₇ crystal for the first time. The detailed spectroscopic properties and energy transfer mechanism of the as-grown crystal were investigated. The results show that the Nd³⁺ ion is not only a very good sensitizer in a Ho³⁺ doped CaLaGa₃O₇ crystal, but also an appropriate deactivated ion with efficient depopulation of the Ho³⁺: ⁵I₇ level for enhancing the 2.86 µm fluorescence emission. And the energy transfer efficiency of Ho³⁺: ⁵I₇→Nd³⁺: ⁴I_13/2 is estimated to be 93%, which indicates that the self-termination effect for the 2.86 µm holmium laser is suppressed successfully in Nd³⁺/Ho³⁺: CaLaGa₃O₇ crystal. Besides, the thermal properties of Nd³⁺: CaLaGa₃O₇ crystal were also studied. In conclusion, the introduction of Nd³⁺ is favorable for achieving an enhanced 2.86 µm emission in Nd³⁺/Ho³⁺: CaLaGa₃O₇ crystal, which can act as a new promising candidate for mid-infrared lasers.