Red to blue upconversion luminescence in Tm~(3+) doped ZrF_4-ZnF_2-AlF_3-BaF_2-YF_3 optical glass

摘要

We report on the preparation and optical spectroscopy analysis of a new fluoride glass in the chemical composition of 20ZrF_4-30ZnF_2-25AlF_3-10BaF_2-15YF_3 with Tm~(3+) as the luminescent ions. Under an UV source, this material has displayed an intense blue emission colour. Upon excitation with a red wavelength at 688 nm (~3H_6 → ~3F_3), this glass has shown two upconverted blue emissions at 452 nm ( ~1D_2 → ~3F_4) and 474 nm ( ~1G_4 → ~3H_6), respectively. Possible mechanisms involved in such upconverted blue emissions are explained via ground state absorption and excited state absorption processes through an energy-level structure diagram of Tm~(3+)(4f~(12)). By the successful application of Judd-Ofelt calculations, the luminescence results have successfully been analysed. Besides obtaining a clear understanding of the optical characteristics of this glass, we have also measured its physical properties such as the refractive indices at three different wavelengths in order to evaluate its light dispersion performance, glass density and other related parameters as well.