Spectral analysis of Pr3+-, Sm3+- and Dy3+-doped transparent GeO2–BaO–TiO2 glass ceramics

In this paper, we present the photoluminescence properties of Pr3+-, Sm3+- and Dy3+-doped germanate glasses and glass ceramics. From the X-ray diffraction measurement, the host glass structure was determined. These glasses have shown strong absorption bands in the near-infrared (NIR) region. Compared to Pr3+-, Sm3+- and Dy3+-doped glasses, their respective glass ceramics have shown stronger emissions due to the Ba2TiGe2O8 crystalline phase. For Pr3+-doped glass and glass ceramic, emission bands centered at 530 nm (3P0→3H5), 614 nm (3P0→3H6), 647 nm (3P0→3F2) and 686 nm (3P0→3F3) have been observed with 485 nm (3H4→3P0) excitation wavelength. Of them, 647 nm (3P0→3F2) has shown bright red emission. Emission bands of 4G5/2→6H5/2 (565 nm), 4G5/2→6H7/2 (602 nm) and 4G5/2→6H9/2 (648 nm) for the Sm3+:glass and glass ceramic, with excitation at 6H5/2→4F7/2 (405 nm) have been recorded. Of them, 4G5/2→6H7/2 (602 nm) has shown a bright orange emission. With regard to the Dy3+:glass and glass ceramic, a bright fluorescent yellow emission at 577 nm (4F9/2→6H13/2) has been observed, apart from 4F9/2→6H11/2 (667 nm) emission transition with an excitation at 454 nm (6H15/2→4I15/2) wavelength. The stimulated emission cross-sections of all the emission bands of Pr3+, Sm3+ and Dy3+:glasses and glass ceramics have been computed based on their measured full-width at half-maxima (FWHM, Δλ) and lifetimes (τm).