Ahmad Marzuki

Spectroscopic Properties of TeO 2 -Bi 2 O 3 -ZnO-PbO Based Tellurite Glasses

Tellurite glasses with molar compositions of 55TeO2–2Bi2O3–[43-x] ZnO–xPbO (in mol%) with x= 1, 2, 3, 4, 5 was fabricated by melt quenching method. Their absorption spectra ranging from ultraviolet to infrared region were measured using UV-VIS-NIR spectrophotometer and FTIR. Minimum losses of all glasses were then estimated from the intersection of the ‘V’ curve formed from the intersection of the extrapolation of the IR edge on the long wavelength side of the spectrum and the scattering loss curve on the short wavelength side of the spectrum. From this work, it was that the estimated minimum loss of the investigated glasses were within the range between 2.31·10-3dB/m and 2.94·10-3 dB/m at wavelength around 5.5 μm.

Physical and optical properties of lead doped tellurite glasses

Physical and optical properties of lead telluride (Pb:TZBN) glasses with composition 55TeO2-(41-x)ZnO-2Bi2O3-2Na2O-xPbO where x = 1.0, 1.5, 2.0, 2.5% mol are presented. UV-VIS-NIR spectra of the glasses in the range of 300 - 800 nm along with their densities and refractive indices at 746 nm were recorded at room temperature. The optical bandgap energy (Eg) has been calculated from the fitting of Tauc plot. On the basis of these results we found that with the increase of Pb2+ content, their refractive indices are increased while their optical bandgaps are decreased. From this experiment, no distinct relationship between the Pb2+ content variation and the electronic polarizability (αO2-) as well as their optical basicity values (A) were observed.

Design of reflective optical fiber sensor for determining refractive index and sugar concentration of aqueous solutions

A reflective optical fiber sensor designed for measuring refractive index and sugar concentration of aqueous solutions is described. Two strains of parallel polymer optical fibers (POF) were wrapped in a bundle such that one of their fibers end cross-sections had the same distance to the mirror surface. The light coming out from one strain of the fiber was reflected by the mirror to the second fiber. Sugar concentration of the aqueous solution filling the space between the fiber ends and the mirror was varied (1.0 M, 1.5 M, 2.0 M, 2.5 M, 3.0 M, 4.0 M, and 5.0 M). It was shown from the experiment that light intensity detected by photo-detector is linearly related to the percentage of the dissolved sugar in the solution as well as the variation of the sugar solution refractive index (R2 = 0.987).

Refractive index measurement of tellurite glasses by using Brewster angle method

This paper presents the refractive index measurement of tellurite glasses using Brewster angle method. We propose a simple experimental method for finding the refractive index of tellurite glasses material using the polarization of light reflected by a dielectric surface near the Brewster angle. The refractive index of tellurite glasses with the composition of [55 TeO2-2Bi2O3-35ZnO-5PbO-(3-x)Na2O-xEr2O3] with x = 0, 0.5, 1, 1.5, 2, 2.5, and 3 % mol are 1.85 for the first sample, 1.87 for the second sample, 1.91 for the third sample, 2.01 for the fourth sample, 2.05 for the fifth sample, 1.83 for sixth sample, and 1.67 for the last sample. The refractive index of tellurite glasses is also compared with the calculation of Lorentz-Lorenz equation.

Absorption Spectra Analysis of Er3+-Doped TeO2-ZnO-Bi2O3 Glasses

Absorption spectra of different composition of tellurite glasses were analyzed in order to estimate their lasing properties. Composition of the investigated tellurite glasses are: 55TeO2-(43-x)ZnO-2Bi2O3-xEr2O3 (x = 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 mol%). Glasses absorption spectra and density were measured at room temperature using UV-VIS-NIR Spectrophotometer and pycnometer, respectively; while their refractive index were measured by implying Brewster’s angle method. Lasing performance of glasses were then analyzed using Judd-Ofelt theory in order to obtain line strength (S), Judd-Ofelt parameters (Ωt, t = 1, 2, 3), and radiative life-times (τ). It is seen that incorporating Er3+ ions of up to 2.5 mol% resulted in decreasing the radiative lifetime of electrons sitting at 4I11/2. From Judd-Ofelt parameters analysis it can be concluded that these tellurite glasses tend to have the covalence nature of Er-O bond and thus represents the asymmetry around the Er3+ ions site.

Optical and physical properties of PbO-modified TeO2-ZnO-Bi2O3 glasses

A series of quaternary tellurite glasses of the form of 55TeO2 –2Bi2O3 –[43-x]ZnO–xPbO (TZBP) were prepared by conventional melt quenching method. The amorphous nature of the glasses has been confirmed using XRD, and their tendency against crystallization has been concluded using DSC. Optical properties of the glasses aimed to gain information on the glasses refractive index, range of transparence, and theoretical minimum loss wewe obtained from measurement using Brewster angle measurement, UV-VIS-NIR spectrophotometer and FTIR. It is shown that the index of refraction increases with increasing PbO content. The IR-edge tends to be red-shifted. No clear tendency of UV-edge was observed. The combined results show that the width of the transparency increase slightly with the increase of Pb2+ content in TZBN glasses.

Optical Properties of Erbium Doped Tellurite Glasses

This paper presents the optical properties of erbium doped tellurite glasses with the composition of 55TeO2-2Bi2O3-35ZnO-5PbO-(3-x)Na2O-xEr2O3 where x = 0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mol% . Refractive index of the glasses was measured using Brewster’s angle method and their optical absorption spectra were measured in spectral range 200 – 1100 nm recorded at room temperature. The results show that the glass refractive index increases with the increase of Er3+ ion content in the glass and the optical band gap energy decreases with the increase of erbium content in the glass.

Evaluation Of The Kinetics Of Crystallization in Aluminum Fluoride Glass Using Isothermal DSC Method

This paper reports the isothermal differential scanning calorimeter (DSC) method used to study the crystallization kinetics of aluminum fluoride glass. The effective activation energy of crystallization (ΔEa/n) was evaluated from the DSC curves using the Johnson‐Mehl‐Avrami equation. The value of the effective activation energy (Ea/n = 113.3 kJ/mol) found from the isothermal DSC curves was slightly higher than that obtained previously with the non‐isothermal DSC method (ΔEc/n = 108.1 kJ/mol). It turns out that both methods can be used in this case.