Double-doped borate glass light guide with high luminance

The luminescence properties of Dy3+ and Tb3+ single- as well as Dy3+/Tb3+ double-doped barium borate glasses are investigated for their potential as light-converter. In double-doped barium borate glass an energy transfer from Dy3+ to Tb3+ is observed, i.e., an intense green luminescence from the doped Tb3+ ions results upon excitation at Dy3+-related absorption bands. Ray-tracing simulations allow for an evaluation of single- and double-doped light guides in different length. Here, the luminous flux and luminance values at the rough output face of a luminescent light guide are determined.