Enhanced emission of 2.7 μm from Er3+/Nd3+-codoped LiYF4 single crystals

An Er3+/Nd3+ co-doped LiYF4 single crystal of ∼Φ 12 mm × 95 mm size with high quality was grown by a Bridgman method. The luminescent properties of the crystals with different Er3+ and Nd3+ concentrations were studied. Compared with the Er3+ single-doped LiYF4 crystal extremely enhanced emission at 2.7 μm from the Er3+/Nd3+ co-doped LiYF4 was observed upon excitation of an 800 nm laser diode. Meanwhile, the green up-conversion emission and near infrared emission at 1.5 μm from Er3+ in the co-doped crystals were effectively restricted. The luminescent mechanisms for the Er3+/Nd3+ co-doped crystals were analyzed and the possible energy transfer processes were proposed. The energy transfer efficiencies for (Er3+:4I13/2, Nd3+:4I9/2) → (Er3+:4I15/2, Nd3+:4I15/2) and (Nd3+:4F3/2, Er3+:4I15/2) → (Nd3+:4I9/2, Er3+:4I9/2) were calculated. It was found that Er3+/Nd3+ co-doped single crystal may be a potential host for 2.7 μm lasers.