Optical properties and tunable luminescence of Ce3+/Dy3+ doped lithium borate glasses for photonic applications

Optical absorption and photoluminescence properties of novel lithium borate glasses, (B2O3)-(MO)-(Li2O)–(Bi2O3) where M stands for Ca, Mg or Sr, doped with Dy and Ce ions have been investigated. The fundamental optical absorption edge of these materials is observed in the region of 315–390 nm, and depends on the nature of alkaline-earth metals used as network modifiers. The photoluminescence spectra of Dy-doped glasses reveal two intensive emission bands in the visible range, which correspond to 4F9/2 →6H15/2 (486 nm) and 4F9/2 →6H13/2 (580 nm) transitions of Dy3+ ions. Ce-doped glasses show one broad band in the visible range, which corresponds to the 2D → 2F5/2 (340 nm) transition of Ce3+ ions. Three photoluminescence lines (980 nm, 1010 nm and 1150 nm) attributed to the Dy3+ ions electronic transitions are observed in the near-IR region of the spectrum for Dy-doped glasses, while only one at 1150 nm is observed for the Dy/Ce co-doped glasses. Peculiarities of excitation energy transfer between rare-earth activator ions are discussed. These glasses are shown to be a promising host matrix for rare-earth doping.