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

Abstract Er 3+ /Tm 3+ :CaLaGa 3 O 7 (abbr. as Er 3+ /Tm 3+ :CLGO) crystal was grown successfully by Czochralski technology and detailed spectroscopic analyses were carried out. The effects of Tm 3+ 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 μ m laser is 980 nm excitation for Er 3+ /Tm 3+ co-doped CLGO crystal. Under 980 nm excitation, the introductions of Tm 3+ are helpful to achieve enhanced mid-infrared (MIR) emissions, as well as reduced near-infrared emissions. Furthermore, the introducing Tm 3+ depopulated the lower laser lever through energy transfer and thus reduced the fluorescence lifetime of Er 3+ : 4 I 13/2 , without significantly affecting the fluorescence lifetime of the upper laser level Er 3+ : 4 I 11/2 , which reduces the self-saturation problem to a great degree. It concludes that this Er 3+ /Tm 3+ :CLGO crystal could be a potential MIR gain media for enhanced 2.7 μ m laser under 980 nm pumping.