Narrow Results

Zinc-phosphate glasses with the addition of B₂O₃ were prepared by using the melt quench technique. These glasses had a mol% composition of 30ZnO-xB₂O₃-(70-x)P₂O₅. The quantity x had values of 10–40 mol%. The mass density of these glasses was found to be in the range of 2.4912–3.0142 g/cm³. The oxygen packing density and molar volume were estimated to lie in the range 192.385–286.026 g-atom/liter and 46.78–31.46 cm³ respectively. The absorption spectra of these glasses were recorded in the range of 190 to 1100 nm. No sharp edges were found in the optical spectra, which confirms the amorphous nature of these glasses. The optical band gap energies were determined to be in the range of 2.40–3.00 eV. A decreasing behavior in optical band gap energy was seen due to the increasing concentration of B₂O₃. The extent of band tailing was worked out from the Urbach plots, which showed an exponential dependence of absorption coefficients on photon energies.

Glasses from xMeO · (100-x)[P₂O₅ · CaO], (MeO=Fe₂O₃, V₂O₅ or (Fe₂O₃ · V₂O₅)) were prepared and investigated using Raman scattering spectroscopy, over compositional range x=0–50% mol. The influence of Fe₂O₃, V₂O₅ or (Fe₂O₃·V₂O₅) content on the structure of P₂O₅·CaO glass matrix was followed. The addition of Fe₂O₃, V₂O₅ or (Fe₂O₃·V₂O₅) determines the modification of the structure of the studied glasses. The Raman spectra of xFe₂O₃(100-x)[P₂O₅·CaO] do not present any absorption bands characteristic to Fe₂O₃ but its evolution is dependent on the iron content. The Raman spectra of xV₂O₅·(100-x)[P₂O₅·CaO] present, besides the bands specific for the matrix, some bands assigned to characteristic vibrations of V–O bonds which are evidenced only for high content of V₂O₅. The evolution of the spectra is dependent on V₂O₅ content. The Raman spectra of x(Fe₂O₃·V₂O₅)·(100-x)[P₂O₅·CaO] system showed that phosphate units are the main structural units of the glass system, iron and vanadium ions are located in the network. The increasing of iron and vanadium content indicate a gradual decrease in the number of bridging oxygen ions and an increase in the number of non-bridging oxygen ions.

We have developed zinc-bismuth-phosphate glasses, which have deformation temperatures under 450°C and refractive indices higher than 1.7, in order to produce an antireflection structure on the surface by a glass-imprinting process. Two-dimensionally arrayed conical cavities of sub-wavelength size were fabricated on a SiC mold by electron lithography and dry etching techniques. The sub-wavelength periodic structure was transferred onto the glass surface by a glass-imprinting process using the mold. The sub-wavelength structure suppressed the reflectance by approximately 90%. A weak maximum was observed in the reflection spectra around 400–500 nm, which decreased in intensity and shifted toward shorter wavelengths with decreasing pitch.

In this study, Yb${}^{3+}$/Ho${}^{3+}$, Yb${}^{3+}$/Tb${}^{3+}$ co-doped, and Yb${}^{3+}$/Ho${}^{3+}$/Tb${}^{3+}$tri-doped phosphate glasses have been prepared by the high-temperature melting method using P₂O₅ as the base material, and these phosphate glasses are characterized as non-crystalline structures by X-ray diffraction. Under 980 nm excitation, highly efficient blue (489 nm), green (545 nm), and red (661 nm) upconversion luminescences can be observed in this glass system, which are attributed to Tb${}^{3+}$: ⁵D₄$\to$⁷F₆, Tb${}^{3+}$: ⁵D₄$\to$⁷F₅, and Ho${}^{3+}$: ⁵F₅$\to$⁵I₈ radiative transitions, respectively. The upconversion emission intensity and excitation power dependence analysis reveal that the blue and green light emissions are three-photon processes, while red light emission is a two-photon process. White light emission can be achieved by adjusting the doping concentration of rare-earth ions in the Yb${}^{3+}$/Ho${}^{3+}$/Tb${}^{3+}$tri-doped phosphate glasses. The CIEchromaticity coordinates of 2Yb${}^{3+}$/0.1Ho${}^{3+}$/0.4Tb${}^{3+}$ tri-doped phosphate glass (0.39, 0.39) under 980 nm excitation are relatively close to those of the standard light source (0.33, 0.33), indicating the potential application of this material in the field of illumination, such asemissive displays, fluorescent lamps and fiber lasers.

In this study, Yb³⁺/Ho³⁺, Yb³⁺/Tb³⁺ co-doped, and Yb³⁺/Ho³⁺/Tb³⁺ tridoped phosphate glasses have been prepared by the high-temperature melting method using P2O5 as the base material, and these phosphate glasses are characterized as non-crystalline structures by X-ray diffraction. Under 980 nm excitation, highly efficient blue (489 nm), green (545 nm), and red (661 nm) upconversion luminescences can be observed in this glass system, which are attributed to ${\text{Tb}}^{3+}:{}^5\text{D}{}_4\to {}^7\text{F}{}_6,{\text{Tb}}^{3+}:{}^5\text{D}{}_4\to {}^7\text{F}{}_5$, and ${\text{Ho}}^{3+}:{}^5\text{F}{}_5\to {}^5\text{I}{}_8$ radiative transitions, respectively. The upconversion emission intensity and excitation power dependence analysis reveal that the blue and green light emissions are three-photon processes, while red light emission is a two-photon process. White light emission can be achieved by adjusting the doping concentration of rare-earth ions in the Yb³⁺/Ho³⁺/Tb³⁺ tri-doped phosphate glasses. The CIE chromaticity coordinates of 2Yb³⁺/0.1Ho³⁺/0.4Tb³⁺ tri-doped phosphate glass (0.39, 0.39) under 980 nm excitation are relatively close to those of the standard light source (0.33, 0.33), indicating the potential application of this material in the field of illumination, such as emissive displays, fluorescent lamps and fiber lasers.