Energy transfer process of Nd3+/Ho3+ co-doped fluoride halide glasses with anion substituted multi-wavelength tunable mid infrared luminescence

Abstract Ho3+ doped ZBLAN glass with 2.0 and 2.9 μm emission has been prepared. In order to further improve the luminescence of Ho3+, halogen ions (Cl, Br, I) are introduced to reduce the maximum phonon energy and phonon state density of the sample. At the same time, Nd3+ is introduced to transfer the energy to Ho3+ pumped with a 793 nm laser(Nd3+:4F5/2,4F3/2→Ho3+:5I6). The effect of different halogen ion on the luminescent properties of the fluoride halide glass is compared. The results show that the luminescent intensity of infrared increases with the introduction of different halogen ions. By comparison, it is found that the sample with I– has the strongest luminescence of 1064 nm, 2.0 μm and 2.9 μm. This is consistent with the calculated J-O intensity parameters. In addition, the 2.0 and 2.9 μm emission of Ho3+ pumped with a 450 nm laser will not disappear. A mid-infrared sample with multi-wavelength excitation and multi-wavelength emission can be obtained. Nd3+/Ho3+ co-doped fluoride halide glass with 1064 nm, 2.0 μm and 2.9 μm luminescence were prepared by melt quenching method. The luminescent mechanism and the energy transfer process between the two ions of Nd3+/Ho3+ co-doped fluoride halide glass are studied. The J-O parameters, luminescence lifetime and absorption emission cross-sectional area of Ho3+ and Nd3+ are calculated, respectively. It is found that the value of Ω2 in the glass matrix increased with the introduction of different halogen ions, while Ω4 and Ω6 did not change obviously in different glass composition. This is because the environment of the crystal field around the rare earth ions has changed. The crystal phase and phonon energy of the sample are analyzed by X-ray diffraction pattern and Fourier transform infrared spectrometer, respectively. Based on the above spectra and data (phonon energy is 634.71 cm–1), it can be predicted that Nd3+/Ho3+ co-doped fluoride halide glass is a potential mid-infrared luminescent material.