Benefit of Nd3+ ions to the ~2.7 µm emission of Er3+: 4I11/2→4I13/2 transition in Nd,Er: CaLaGa3O7 laser crystal

Nd3+ was introduced into Er3+: CaLaGa3O7 crystal for an enhanced ~2.7 µm emission. The structure parameters of Er: CaLaGa3O7 and Nd,Er: CaLaGa3O7 crystals are determined by the X-ray Rietveld refinement method. The effects of Nd3+ on the spectroscopic properties and mutual energy transfer mechanisms were investigated. It is found that Nd3+ greatly improves the absorption pump efficiency and thus enhances the Er3+ ~ 2.7 µm emission by nearly 5 times, meanwhile, quenches the ~ 1.5 µm near-infrared emission. Therefore, the self-termination effect for ~ 2.7 µm erbium laser is suppressed successfully. Furthermore, the energy transfer efficiencies of Nd3+→Er3+ and Er3+→Nd3+ are estimated to be 92.3% and close to 100%, respectively. Besides, the radiative transfer microscopic parameters between Nd3+ and Er3+ were theoretically analyzed. The results indicate that the introduction of Nd3+ is very beneficial in achieving ~ 2.7 µm laser in Er3+: CaLaGa3O7 crystal, which could act as a potential gain media for LD pumped MIR laser.