Intense 2.7 μm emission from Er3+/Tm3+/Pr3+ triply doped LiYF4 single crystal grown by Bridgman method

• An Er3+/Tm3+/Pr3+ triply doped LiYF4 single crystal with high quality has been grown by Bridgman method.
• An enhanced emission from 2600 nm to 2800 nm was obtained.
• The energy transfer mechanism of 2.7 μm emission between Er3+, Tm3+ and Pr3+ ions was analyzed.

Laser crystals of Er3+ singly, Er3+/Tm3+, Er3+/Pr3+ doubly and Er3+/Tm3+/Pr3+ triply doped LiYF4 are grown by a vertical Bridgman method. The luminescent properties of the crystals were investigated. An intense emission at 2.7 μm can be obtained by using 980 nm laser diode excitation in the triply doped LiYF4 crystals. Meanwhile, the green and red up-conversion emission and near infrared emission at 1.5 μm from Er3+ in the triply doped crystals were effectively restricted. The possible energy transfer processes and the luminescent mechanisms for the Er3+/Pr3+/Tm3+ triply doped crystals were proposed. Decay curve fitting using a Inokuti–Hirayama expression indicates a dipole–dipole energy transfer from Er3+ to Pr3+, and Er3+ to Tm3+, which is consistent with the expected cross-relation scheme. These results suggest that the Er3+/Tm3+/Pr3+ triply doped crystal may be considered as a promising material for a 2.7 μm laser.

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