Enhanced 2.0 μm emission in oxyfluoride glass-ceramics containing nanocrystals MF 2 (MF 3): Ho 3+,Tm 3+ (M = Ca, Ba, and La)

Abstract

Transparent glass-ceramics containing MF 2(MF 3):Ho 3+,Tm 3+ (M = Ca, Ba, and La) nanocrystals have been prepared by melt quenching and subsequent thermal treatment. X-ray diffraction and transmission electron microscopy analysis confirmed the precipitation of MF 2 (MF 3) nanocrystals among the glass matrix. Energy-dispersive X-ray spectroscopy results evidenced the incorporation of Tm 3+ and Ho 3+ into the MF 2 nanocrystals. Intense 2.0 μm emission originating from the Ho 3+: 5I 7 → 5I 8 transition was achieved upon excitation with 808 nm laser diode. A large ratio of the forward Tm 3+ → Ho 3+ energy transfer constant to that of the backward process indicated high efficient energy transfer from Tm 3+ ( 3F 4) to Ho 3+ ( 5I 7), and benefited from the reduced ionic distances of Tm 3+–Tm 3+ and Tm 3+–Ho 3+ pairs and low phonon energy environment with the incorporation of rare earth ions into the precipitated MF 2 nanocrystals. The results indicate that oxyfluoride glass-ceramic is a promising candidate for 2.0 μm laser.