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Here, we present a novel method for the separation of overlapping emission spectral lines corresponding to nonlinear processes, which differ by effective nonlinearity with respect to the pump field power. The method exploits the factorization of wavelength and pumping power dependencies of the components processes contributions to the total luminescence. The advantage of our method is an ability to be self-testing and robust with respect to noise and experimental imperfections. We successfully demonstrate functionality of the method in the experiment with up-conversion luminescence of the fluorophosphate glass doped with rare-earth ions Yb³⁺ and Tm³⁺ pumped by 975 nm CW diode laser. Full article

This paper presents the numerical simulation of the ultrasonic wave transmittance utilizing the elastodynamic finite integration technique (EFIT). With this methodology, it is possible to simulate the propagation of the ultrasound in a medium with a relatively low computational cost. The capability of this technique for determining the elastic properties of fluorophosphate and the aluminosilicate glasses is described in detail. The elastic constants of the glasses were calculated from the theoretically predicted longitudinal and transversal sound velocities and compared with the corresponding experimental data. Furthermore, the calculated and experimental elastic properties of the fluorophosphate and aluminosilicate glasses were correlated with the structural peculiarities of these glasses. This simulation technique is also suitable for unveiling the existence of possible defects in the glasses by comparing the experimental and simulation data. The EFIT technique is shown to be a very useful tool in order to provide fast and easy-to-acquire data regarding also the structural characteristics of various glassy systems. This can be used in conjunction with other spectroscopic techniques which can prove to be extremely useful for the non-destructive testing of vitreous materials. The latter can prove very important when vitreous materials used in optical or optoelectronic applications need continuous monitoring in order to ensure their optimum operation and functionality with limited intervention. The main contribution of this paper is the treatment of numerical time-domain modeling of 2D acoustic wave propagation in a viscoelastic medium by implementing the elastodynamic finite integration technique (EFIT). Full article

This communication reports the intrinsic luminescence of tin chlorophosphate glasses. The glass maintains the low melting point characteristics of tin fluorophosphate glasses, and exhibits a red-shifted and broadened excitation wavelength peak. Tin chlorophosphate glasses can exhibit a broadband luminescence of 400–700 nm under an excitation of 380–430 nm. Furthermore, the introduction of ZnCl₂ into tin chlorophosphate glasses can considerably enhance the luminescence without affecting their low-melting characteristics. The luminescence intensity can be increased fourfold, with the enhancement attributed to the reduced visible absorption, improved dispersion of Sn²⁺ ions, and the energy exchange between Sn²⁺ and Zn²⁺ in the glasses owing to the addition of ZnCl₂. Full article

The impact of the progressive addition of ZnO up to 5 mol% on the thermal, structural, and optical properties of Er³⁺-doped phosphate glasses within the system NaPO₃-NaF-ZnO-Ag₂O is discussed. The glass network was found to depolymerize upon the addition of ZnO. This promotes a slight increase in the intensity of the emission at 1.5 µm as well as enhances the silver ions clustering ability under the heat treating. The Ag-nanoparticles formed after moderate heat-treatment can further enhance the emission at 1.5 µm, whereas an excessive amount of the clusters leads to the opposite effect. The addition of ZnO helps to slightly increase the glass ability of the system. The crystallization behavior study revealed that surface crystallization is observed for all the glasses. It is found that even a small ZnO addition changes the crystalline phases formed after devitrification. Moreover, the addition of ZnO decreases the crystallization tendency of the glass. Full article

Glasses with the system (84.60-x) NaPO₃-5 ZnO-(9.40-x) NaF-x Ag₂O-1 Er₂O₃, (x = 0, 2, 4, and 6) (mol%) were synthesized by the conventional melt-quenching method. The impact of the addition of Ag₂O on the physical, thermal, structural, and optical properties of the glasses is discussed. The Judd-Oflet analysis was used to evaluate the radiative properties of the emission transitions of the glasses. The enhancement of luminescence properties due to Ag₂O is discussed in terms of consequent changes in the local electromagnetic field, symmetry, and the ligand field around the Er³⁺ ion. The heat treatment of the glass was performed in order to precipitate Ag nanoparticles (NPs), which form as a layer at the surface of the heat-treated glasses as confirmed using scanning electron microscopy (SEM). The Ag NPs were found to increase the intensity of the emission at 1.5 µm. Full article