Enhanced 2.7 μm emission from diode-pumped Er3+/Pr3+ co-doped LiYF4 single crystal grown by Bridgman method

In this paper, we report the Bridgman growth of a Er3+/Pr3+ co-doped LiYF4 single crystal with a size of ~Φ12 mm × 140 mm and the observation of enhanced 2.7 μm mid-IR emission of the crystal. The emission characteristics and energy transfer of various parts of crystal upon excitation of a 980 nm laser diode are investigated. Population inversions between 4I13/2 and 4I11/2 levels have been achieved. The energy transfer processes are studied based on the I–H model, and the interaction between Er3+ and Pr3+ is confirmed to be electric dipole–dipole. The large energy transfer efficiency of 82.99% and excellent optical transmission indicate that this Er3+/Pr3+ co-doped LiYF4 single crystal has potential applications in 2.7 μm laser.