Role of Nd3+ nanoparticles on enhanced optical efficiency in borotellurite glass for optical fiber

The main problem of commercial silicate glass fiber is its high-loss and weak optical efficiency. It is very important to produce non-silicate glass fiber with low-loss and high optical efficiency. In this work, low-loss and high optical efficiency of Nd3+ nanoparticles doped borotellurite glass had been produced. The analysis of FTIR spectra shows the presence of functional vibration of tellurite network. The refractive index of borotellurite glass was enhanced in between 1.947 and 2.045 with the increment of Nd3+ nanoparticles. Several excitation bands within UV–Vis range due to the effect of Nd3+ nanoparticles was perceived originating from the ground state 4I9/2 to the excited states 2P3/2, 4G7/2, 4G5/2, 4F9/2, 4F7/2, 4F5/2 and 4F3/2. The glass system shows tendency towards semiconducting behavior as the value of Fermi energy, EF decreases. The high intensity of red emission was found from Nd3+ nanoparticles doped borotellurite glass. Hence, this Nd3+ nanoparticles doped borotellurite glass has immense potential for the development of fiber amplifiers and lasers. Keywords: Borotellurite glass, Neodymium nanoparticles, Rare-earth oxid

Optical basicity and electronic polarizability of zinc borotellurite glass doped La3+ ions

Zinc borotellurite glasses doped with lanthanum oxide were successfully prepared through melt-quenching technique. The amorphous nature of the glass system was validated by the presence of a broad hump in the XRD result. The refractive index of the prepared glass samples was calculated by using the equation proposed by Dimitrov and Sakka. The theoretical value of molar refraction, electronic polarizability, oxide ion polarizability and metallization criterion were calculated by using Lorentz-Lorenz equation. Meanwhile, expression proposed by Duffy and Ingram for the theoretical value of optical basicity of multi-component glasses were applied to obtain energy band gap based optical basicity and refractive index based optical basicity. The optical basicity of prepared glasses decreased with the increasing concentration of lanthanum oxide. Metallization criterion on the basis of refractive index showed an increasing trend while energy band gap based metallization criterion showed a decreasing trend. The small metallization criterion values of the glass samples represent that the width of the conduction band becomes larger which increase the tendency for metallization of the glasses. The results obtained indicates that the fabricated glasses have high potential to be applied on optical limiting devices in photonic field. Keywords: Borotellurite glasses, Refractive index, Electronic polarizability, Oxide ion polarizability, Optical basicity, Metallization criterio

Linear and nonlinear optical properties of Gd3+ doped zinc borotellurite glasses for all-optical switching applications

In this work, linear and nonlinear optical parameters of zinc borotellurite glasses doped with Gd3+ have been studied for all-optical switching applications. A series of gadolinium zinc borotellurite glasses were synthesized by using conventional melt quenching technique. Optical absorption spectra were recorded by UV–vis spectroscopy. From the optical absorption spectra, the cut-off wavelength, optical band gap, Urbach energy and refractive index have been determined and are related to the structural changes in the glass systems. The nonlinear optical properties of Gd3+ doped glasses are investigated by using Z-scan technique. The values of nonlinear refractive index and absorption coefficient with closed and opened apertures of the Z-scan, respectively, were determined for proper utilization in nonlinear optical devices. Keywords: Gadolinium, Rare earth, Borotellurite glass, Optical band gap, Refractive index, Nonlinear optical propertie

Hypersensitivity and nephelauxetic effect of Er3+ in bismuth tellurite glass system

The optical absorption and emission properties of 20Li2O-xBi2O3-(78-x)TeO2-1Er2O3-1Ag glass system had been analyzed to investigate the hypersensitivity shift and its mechanism. According to the Covalent model, the hypersensitive shift indicated by the drop of F2 at x = 5 mol% can be attributed to charge transfer from O2– ligands to Er3+ ions meanwhile according to the Dielectric screening model, drop of F2 may due to Er3+ ions contraction. The dynamic coupling mechanism was used to explain hypersensitivity transition probabilities in non-centrosymmetric systems. The addition of Bi2O3 may modify the site symmetry of Er3+ ions and oxygen to a high asymmetry τ2, resulting in an asymmetrical electron distribution, thus increasing Er-O covalency, as shown by the maximum Ω2 value at x = 5 mol%. The Er3+ ions site symmetry was investigated using Hamiltonian crystal field fitting in the frame of the D4 point symmetry model, which yielded maximum crystal field strength Nv at x = 5 mol%, indicating low point symmetry distortion of the Er3+ ions site symmetry