2–3 μm mid-infrared luminescence of Ho3+/Yb3+ co-doped chloride-modified fluorotellurite glass

In this paper, Ho3+/Yb3+ co-doped chloride-modified fluorotellurite glasses with 2-3 μm mid-infrared luminescence are prepared. By measuring and investigating the transmission spectra and emission spectra, the prepared glasses show a high transmittance (91 %) and low maximum phonon energy (813 cm-1). Based on the measured absorption spectra, the Judd-Ofelt parameters and radiation characteristics were calculated in depth. In addition, with the assistance of phonons, the energy transfer between Ho3+/Yb3+ ions further increases the mid-infrared fluorescence intensity. The calculated emission cross-section at 2.0 μm and 2.85 μm reach 16.47 × 10-21 cm2 and 7.8 × 10-21 cm2, respectively. It is worth mentioning that the quantum efficiencies of Ho3+: 5I7→5I8 and 5I6→5I7 reach 51.47 % and 84.14 % respectively. The results having also in mind good thermal stability (ΔT = 102℃) and refractive index (n = 1.645) indicate that this glass has a promising application for the study of fiber lasers in the mid-infrared band.