Optical spectroscopy and optical waveguide fabrication in Eu3+ and Eu3+/Tb3+ doped zinc-sodium-aluminosilicate glasses

Optical and spectroscopic properties of 2.0% Eu(PO3)3 singly doped and 5.0% Tb(PO3)3-2.0% Eu(PO3)3 codoped zinc-sodium-aluminosilicate glasses were investigated. Reddish-orange light emission, with x=0.64 and y=0.36 CIE1931 chromaticity coordinates, is obtained in the europium singly doped glass excited at 393 nm. Such chromaticity coordinates are close to those (0.67,0.33) standard of the National Television System Committee for the red phosphor. When the sodium-zinc-aluminosilicate glass is co-doped with Tb3+ and Eu3+, reddish-orange light emission, with (0.61,0.37) CIE1931 chromaticity coordinates, is obtained upon Tb3+ excitation at 344 nm. This reddish-orange luminescence is generated mainly by 5D0→7F1 and 5D0 →7F2 emissions of Eu3+, europium being sensitized by terbium through a non-radiative energy transfer. From an analysis of the Tb3+ emission decay curves it is inferred that the Tb3+→Eu3+ energy transfer might take place between Tb3+ and Eu3+ clusters through a short-range interaction mechanism, so that an electric dipole-quadrupole interaction appears to be the most probable transfer mechanism. The efficiency of this energy transfer is about 62% upon excitation at 344 nm. In the singly doped and codoped glasses multimode optical waveguides were successfully produced by Ag+-Na+ ion exchange, and they could be characterized at various wavelengths.