Rare earths in nanocrystalline glass–ceramics

Nd3+-doped TeO2–PbF2–AlF3 glasses for laser applications

“…The values obtained for the three Nd 3+ concentrations, which in the maxima coincide with those of r eff (k 0 ) (Eq. (13)), are presented in Table 3, and are Table 3 Experimental parameters obtained for the 4 similar to other glass compositions. Once the r em (k) was calculated, the absorption cross section r abs (k) can be obtained using the McCumber theory (Eq.…”

“…The bands under 300 cm À1 correspond to the optical modes of TeO 2 such as the translatory and rotatory (or librations) vibrations, however the collective modes of the local structures and heavy metal vibrational modes of the (PbF 2 ) and (AlF 3 ) could be also attributed [28][29][30]. The bands from 250 cm À1 to 700 cm À1 can be assigned to the vibrational modes of the stretching vibrations of TeO 3+1 and TeO 4 , where the most intense band at $450 cm À1 corresponds to the symmetric stretching vibrations of Te-O-Te intra-chain bridges and the band at 660 cm À1 is generated by the stretching vibrations of TeO 4 . On the other hand, the asymmetric stretching at 750 cm À1 can be assigned to the TeO 3 and/or TeO 3+1 trigonal pyramids [31,32].…”

“…Among the common requirements that must fulfill the glasses hosts highlight wide transmission ranges from ultraviolet (UV) to mid-infrared (IR), good chemical, mechanical and thermal stabilities, high nonlinear refractive index, and relatively low-energy phonon, which reduce the multiphonon non-radiative probabilities and, consequently, increase the quantum yields. In this regard, glasses such as chalcogenides, borates, fluorozirconates, fluorides, silicates [4][5][6] and tellurites have been the subject of several extensive studies.…”

“…Nevertheless, for suitable applications in ultra-fast spectroscopic investigations and non-heating laser processing it is necessary to develop highaverage power, high-efficiency, compacts and low-cost femtosecond lasers. In this regard, the transitions at 4 ($1340 nm) in the NIR-range are the most suitable for the commented applications [6]. We will focus on the more intense band corresponding to the 4 F 3/2 ?…”

Influence of active admixtures onto tellurite glass refractive index

“…1). According to [10] formation of the b-PbF 2 phase during thermal treatment of glass is favoured by the incorporation of RE ions in the crystalline phase, playing the role of heterogeneous nucleating agents and partially replacing the Pb 2+ . Presence of the crystalline phase within the range of the effect occurrence was proved with X-ray phase analysis XRD (Table 2, Figs.…”