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

Nd3+ sensitized Er3+:I-4(11/2)-> I-4(13/2) mid-infrared (MIR) emission around 2.7 mu m was achieved in SrGdGa3O7 single crystal for the first time. The effect of Nd3+ on the absorption, near-infrared (NIR) and MIR fluorescence properties of Er3+ ions were investigated. It is found that Nd3+ greatly improves the absorption pump efficiency and thus enhances the Er3+ similar to 2.7 mu m emission by nearly 10 times under 808 nm laser diode (LD) excitation, at the same time quenches the 1.5 mu m near-infrared emission of the lower level Er3+:I-4(13/2) and thus suppresses the self-saturation problem effectively. The luminescent mechanism for the Nd3+/Er3+:SrGdGa3O7 crystal was analyzed and the possible energy transfer processes were proposed. The energy transfer efficiencies of Nd:F-4(3/2)->:(ErI11/2)-I-4 and Er:I-4(13/2)-> Nd:I-4(15/2) are estimated to be 85.8% and close to 100%, respectively. The results indicate that the introduction of Nd3+ is very beneficial in achieving 2.7 mu m laser in Er3+:SrGdGa3O7 crystal which could act as a potential gain media for LD pumped MIR laser. (C) 2014 Elsevier Ltd. All rights reserved.