The influence of Er3+ ions on the spectroscopic and lasing characteristics of alkaline earth titanium borate glasses for photonic applications

Abstract

Alkaline earth titanium borate glasses doped with different ratios of Er3+ ions were fabricated using standard melt quenching technique. The density of the glasses increased from 3.652 to 3.762 g/cm3 as the ratio of Er3+ ions increased from 0 to 5.640 × 1020 cm−3. The gaussian deconvolution of the Raman and FTIR spectra was investigated, and the distinctive spectral vibrational bands were assigned. The UV–Vis–NIR absorption spectra of the erbium doped glasses exhibit nine bands located at 1531, 980, 808, 654, 520, 490, 446, 408, and 377 nm due to the electronic transitions of Er3+ ions from the ground level 4I15/2 to the higher excited levels 4I13/2, 4I11/2, 4I9/2, 4F9/2, 2H11/2, 4F7/2, 4F3/2, 2G9/2, and 4G11/2, respectively. The structural and luminescent properties of the erbium doped glasses were investigated by calculating Judd – Ofelt intensity parameters, radiative transition probabilities, branching ratio, lifetime, full width at half maximum (FWHM), and gain bandwidth (FWHM × σemis). The intensity parameters followed the trend as Ω2> Ω6> Ω4 for all glasses. The values of Ω2 decreased from 5.2079 × 10−20 to 3.8133 × 10−20 cm2 and that of Ω4 decreased from 0.7402 × 10−20 to 0.5939 × 10−20 cm2 as the ratio of Er3+ ions increased. The high laser efficiency of the studied glasses were verified by the high values of the radiative lifetime, branching ratio, FWHM, and gain bandwidth. The gain spectra for BaTiBEr3 and BaTiBEr5 glasses covered the conventional (1530–1565 nm) and long (1565–1625 nm) communication bands. Moreover, the high values of the FWHM and gain bandwidth for BaTiBEr3 and BaTiBEr5 glasses, suggested their suitability for photonic applications in the near infrared region and broadband optical fiber amplifiers.