A wet non-conventional method for preparing aluminophosphate glasses is presented.
Aluminophosphate glasses belonging to the oxide system Li2O-BaO-Al2O3-La2O3-P2O5, doped with
rare-earth ions (Pr3+, Er3+, Gd3+, and Yb3+) were obtained. The influence of the doping ions on the
optical properties of the phosphate glasses has been investigated in relation with micro-structural
and local electronic phenomena The optical behavior of Li2O-BaO-Al2O3-La2O3-P2O5 glasses
doped with 3% mol. rare-earth ions has been studied by ultra-violet-visible-near-infra-red (UV-VISNIR)
spectroscopy. The transmission spectra revealed electronic transitions between 4f and 6s inner
orbital of the rare-earth ions. Structural information via optical phonons was provided by infra-red
(IR) absorption spectra in the range 400-4000 cm-1. IR optical phonons are characteristic for the
vitreous phosphate network, showing out the glass network-forming role of P2O5. The absorption
spectra present the main PO2 and P-O-P symmetrical stretch modes besides P-O-P bend mode, P-OH,
P=O, PO3
2-, asymmetrical and symmetrical vibration modes. Fluorescence spectra of the rareearth-
doped aluminophosphate glasses, in the visible range, were obtained by laser excitation at
514.5 nm. The fluorescence signals revealed specific electronic transitions, which provide visible
and near-infra-red emission. Glasses containing rare-earth ions exhibit luminescence at the
following wavelengths: Pr3+ ions at 820 nm and 880 nm, Er3+ ions at 520 nm, 550 nm and 560 nm,
Gd3+ ions at 530 nm, 540 nm, 550 nm 820 and 880 nm, Yb3+ions at 530 nm, 540 nm, 550 nm and
980 nm.
Non-equilibrium longitudinal and transverse optical phonons in terahertz quantum cascade lasers
