Efficient mid-infrared laser under different excitation pump wavelengths

A laser operating at 2.8 mu m in a lightly doped Er3+ : SrF2 crystal is analyzed first for different excitation pump wavelengths: 972 nm and 1532 nm. A maximum output power of 814 mW was obtained by a 972-nm commercial laser diode, and the corresponding slope efficiency was 30.4%. Laser emission under 1532-nm excitation was also achieved by efficient upconversion energy transfers. This could be an effective technique for realizing a compact and efficient upconversion laser capable of emitting in the mid-infrared regime. (C) 2017 Optical Society of America