Enhanced 2.7 μm emission and its origin in Nd3+/Er3+ codoped SrGdGa3O7 crystal.

Nd 3+ sensitized Er 3+ : 4 I 11/2 → 4 I 13/2 mid-infrared (MIR) emission around 2.7 μm was achieved in SrGdGa 3 O 7 single crystal for the first time. The effect of Nd 3+ on the absorption, near-infrared (NIR) and MIR fluorescence properties of Er 3+ ions were investigated. It is found that Nd 3+ greatly improves the absorption pump efficiency and thus enhances the Er 3+ ~2.7 μm emission by nearly 10 times under 808 nm laser diode (LD) excitation, at the same time quenches the ~1.5 μm near-infrared emission of the lower level Er 3+ : 4 I 13/2 and thus suppresses the self-saturation problem effectively. The luminescent mechanism for the Nd 3+ /Er 3+ :SrGdGa 3 O 7 crystal was analyzed and the possible energy transfer processes were proposed. The energy transfer efficiencies of Nd: 4 F 3/2 →Er: 4 I 11/2 and Er: 4 I 13/2 →Nd: 4 I 15/2 are estimated to be 85.8% and close to 100%, respectively. The results indicate that the introduction of Nd 3+ is very beneficial in achieving 2.7 μm laser in Er 3+ :SrGdGa 3 O 7 crystal which could act as a potential gain media for LD pumped MIR laser. [ABSTRACT FROM AUTHOR]