The influence of Tm3+ to enhance 2.7 μm mid-infrared emission of Er3+ in CaLaGa3O7 crystal

Abstract

Abstract Er3+/Tm3+:CaLaGa3O7 (abbr. as Er3+/Tm3+:CLGO) crystal was grown successfully by Czochralski technology and detailed spectroscopic analyses were carried out. The effects of Tm3+ on the spectroscopic properties and mutual energy transfer mechanisms were investigated. It is found that the more suitable pumping scheme for laser applications at 2.7 μm laser is 980 nm excitation for Er3+/Tm3+ co-doped CLGO crystal. Under 980 nm excitation, the introductions of Tm3+ are helpful to achieve enhanced mid-infrared (MIR) emissions, as well as reduced near-infrared emissions. Furthermore, the introducing Tm3+ depopulated the lower laser lever through energy transfer and thus reduced the fluorescence lifetime of Er3+ : 4I13/2, without significantly affecting the fluorescence lifetime of the upper laser level Er3+ : 4I11/2, which reduces the self-saturation problem to a great degree. It concludes that this Er3+/Tm3+:CLGO crystal could be a potential MIR gain media for enhanced 2.7 μm laser under 980 nm pumping.