The Role of Bi₂O₃ on the Thermal, Structural, and Optical Properties of Tungsten-Phosphate Glasses

Abstract

Glasses in the ternary system (70 - x)NaPO(3)-30WO(3)-xBi(2)O(3), with x = 0-30 mol %, were prepared by the conventional melt-quenching technique. X-ray diffraction (XRD) measurements were performed to confirm the noncrystalline nature of the samples. The influence of the Bi(2)O(3) on the thermal, structural, and optical properties was investigated. Differential scanning calorimetry analysis showed that the glass transition temperature, T(g), increases from 405 to 440 °C for 0 ≤ x ≤ 15 mol % and decreases to 417 °C for x = 30 mol %. The thermal stability against devitrification decreases from 156 to 67 °C with the increase of the Bi(2)O(3) content. The structural modifications were studied by Raman scattering, showing a bismuth insertion into the phosphate chains by Bi-O-P linkage. Furthermore, up to 15 mol % of Bi(2)O(3) formation of BiO(6) clusters is observed, associated with Bi-O-Bi linkage, resulting in a progressive break of the linear phosphate chains that leads to orthophosphate Q(0) units. The linear refractive index, n(0), was measured using the prism-coupler technique at 532, 633, and 1550 nm, whereas the nonlinear (NL) refractive index, n(2) was measured at 1064 nm using the Z-scan technique. Values of 1.58 ≤ n(0) ≤ 1.88, n(2) ≥ 10(-15) cm(2)/W and NL absorption coefficient, α(2) ≤ 0.01 cm/GW, were determined. The linear and NL refractive indices increase with the increase of the Bi(2)O(3) concentration. The large values of n(0) and n(2), as well as the very small α(2), indicate that these materials have large potential for all-optical switching applications in the near-infrared.

Highly nonlinear Pb2P2O7-Nb2O5 glasses for optical fiber production

“…Glass thermal stability against crystallization was evaluated by using the thermal stability parameter T, defined by T x -T g , which increases up to 40 mol % of Nb 2 O 5 . varying WO 3 concentration, which has been also related with an increase of the network connectivity due to WO 6 octahedral units insertion into the lead phosphate chains [1,14]. In addition, the samples present good thermal stability against crystallization, with ΔT values above 100 C up to ~ 250 °C, as seen in Figure 2.…”

“…devices. However, the introduction of transition metal oxide such as WO 3 , Nb 2 O 5 , MoO 3 and TiO 2 , which have several different oxidation states and high coordination number at high concentrations, gives glass formation features when combined with others glass former compound, increasing mechanical and chemical stability [14,15]. Notably, niobium phosphate glasses might be used in a varied range of applications, such as rare-earth ion hosts for laser materials, optical fibers, lenses, optical switches, electrodes and others photonics devices [16][17][18].…”

Ultrafast optical Kerr gate of bismuth–plumbum oxide glass for time-gated ballistic imaging

“…Therefore, various materials, such as inorganic glasses [5], organic or polymeric materials [6,7], and semiconductors [8] have been prepared via different methods. Among these various promising optical materials, oxide glasses containing heavy atomic (ionic) oxides, such as bismuthate, tellurite, or plumbum oxides, have stimulated great interest because they have the advantages of high chemical and thermal stability, simple fabrication process, low optical loss over large spectral ranges, and high optical damage threshold [9][10][11][12]. Particularly, many bismuth-based glasses with heavy atomic (ionic) oxides present large third-order optical nonlinearities for the applications in ultrafast all-optical switches [13], optical power limiters [14], and wavelength division multiplexing devices [15].…”

Nonlinear optical properties of Bi2O3-GeO2 glass at 800 and 532 nm

“…The large third-order optical susceptibility, v ð3Þ , due to the high polarizability of the heavymetal ions, allows applications of HMO glasses in optical limiting, optical amplifiers, and all-optical switching. [1][2][3][4][5][6][7][8][9][10][11][12] The HMO glasses containing bismuth oxide, Bi 2 O 3 , present large nonlinearity because of the high polarizability of the Bi 3þ ion due to its lone-electron pair in the valence shell and its large ionic radius. Moreover, with the introduction of Bi 2 O 3 in a HMO glass network, the number of nonbridging oxygen grows, and thus, the optical refractive and absorptive properties of the material increase.…”

“…The NL properties of glasses with Bi 2 O 3 were discussed by various authors that report large NL refractive index and high twophoton absorption (TPA) coefficients for certain glass compositions. [7][8][9][12][13][14][15] For instance, the influence of Bi 2 O 3 on the structural, thermal, and NL optical properties of phosphate glasses was investigated recently. 9 The results obtained show that the NL refractive indices increase with the increase of the Bi 2 O 3 concentration.…”