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Sudhakar Reddy B.,Gwangju Institute of Science and Technology | Hwang H.-Y.,Gwangju Institute of Science and Technology | Jho Y.-D.,Gwangju Institute of Science and Technology | Seung Ham B.,Gwangju Institute of Science and Technology | And 4 more authors.
Ceramics International | Year: 2015

The optical properties of borotellurite glasses doped with Nd3+ ions or codoped with Er3+-Yb3+ ions are investigated, in order to evaluate the potential application of these types of glass in laser systems and amplifier materials. The Judd-Ofelt (JO) model is used to determine the absorption intensities of both types of glass so as to establish the J-O intensity parameters (Ωλ). The J-O intensity parameters are then used to determine the various radiative parameters viz., the radiative transition probabilities (AR), branching ratios (βR), stimulated emission cross-sections (σe), full width half maxima (Δλp) and radiative lifetimes (τR) of both types of glass, which are also compared to the equivalent parameters for other host glasses. It has been shown that Yb3+ acts as an Er3+ sensitizer and contributes largely to the improvement of the spectroscopic properties of the glasses that is codoped with Er3+-Yb3+. The obtained values ofAR, βR, τR, σe and Δλp for the Nd3+- and Er3+-doped glass show that both the 4F3/2→4I11/2 transition at 1.06 μm in the Nd3+ case and the 4I13/2→4I15/2 transition at 1.56 μm for the Er3+ case exhibit better NIR luminescence at a level suitable for photonic device applications. The potential of the glasses examined in this study, due to their promising gain media, is also discussed in terms of the development of solid state NIR lasers and optical amplification for telecommunication applications. © 2014 Elsevier Ltd and Techna Group S.r.l.


Madhukar Reddy C.,Sri Venkateswara University | Dillip G.R.,Sri Venkateswara University | Mallikarjuna K.,Sri Venkateswara University | Zulifiqar Ali Ahamed S.,Sri Venkateswara University | And 2 more authors.
Journal of Luminescence | Year: 2011

Lead containing calcium zinc sodium fluoroborate glasses (LCZSFB) with molar composition of 20PbO5CaO5ZnO10NaF(60-x) B2O3x Sm2O3, (x=0.1, 0.25, 0.5, 1.0 and 2.0 mol%) were prepared and investigated by the XRD, FTIR, optical absorption, photoluminescence and decay curve analysis. JuddOfelt theory was applied to the experimental oscillator strengths to evaluate the phenomenological JO intensity parameters Ωλ (λ=2, 4 and 6). Using the JO intensity parameters as well as from the emission and decay measurements, various radiative parameters such as transition probabilities (AR), radiative lifetimes (τR), measured lifetimes (τm), calculated branching ratios (βR), measured branching ratios (βm), effective bandwidth (Δλeff) and stimulated emission cross sections σ(λp) have been calculated for the excited 4G5/2 luminescent level. The nature of decay curves of 4G5/2 level for different Sm3 ion concentrations in all LCZSFB glasses has been analyzed and the lifetimes are noticed to decrease with increase of concentration. The concentration quenching has been attributed to the energy transfer through the cross-relaxation between Sm3 ions. Based on these results, the utility of Sm3 ions doped lead containing fluoroborate glasses as laser active materials in the visible region is discussed. © 2011 Elsevier B.V. All rights reserved.


Sailaja S.,Sri Venkateswara Degree College | Nageswara Raju C.,Sri Venkateswara Degree College | Adinarayana Reddy C.,Sri Venkateswara Degree College | Deva Prasad Raju B.,Sri Venkateswara University | And 2 more authors.
Journal of Molecular Structure | Year: 2013

This article reports on the optical properties of cadmium bismuth borate (CdBiB) glasses doped with various concentrations of Sm3+ ions. FT-IR spectra of Sm3+:CdBiB glasses have been used to identify the functional groups present in the composition of the glasses. The emission spectra of Sm3+:CdBiB glasses have shown an intense reddish-orange emission at 600 nm (4G5/2 → 6H 7/2). From the absorption spectrum, the experimental oscillator strengths were determined and have been used to calculate the Judd-Ofelt (J-O) intensity parameters. By using the J-O intensity parameters, various radiative properties have been studied and computed for the various transitions of Sm 3+:CdBiB glasses. Based on the values of stimulated emission cross section, radiative transition rate and the branching ratio of the emission transition 4G5/2 → 6H7/2, it is suggested that 1.0 mol% of Sm3+:CdBiB glass is the promising luminescent material towards lasing applications. The nature of luminescence decay curves of 4G5/2 level with different concentrations of Sm3+:CdBiB glasses are also reported. © 2013 Elsevier B.V. All rights reserved.


Nageswara Raju C.,Sri Venkateswara Degree College | Adinarayana Reddy C.,Sri Venkateswara Degree College | Sailaja S.,Sri Venkateswara Degree College | Seo H.J.,Pukyong National University | Sudhakar Reddy B.,Sri Venkateswara Degree College
Luminescence | Year: 2012

This article reports on the optical properties of Er 3+ ions doped CdO-Bi 2O 3-B 2O 3 (CdBiB) glasses. The materials were characterized by optical absorption and emission spectra. By using Judd-Ofelt theory, the intensity parameters ω λ (λ = 2, 4, 6) and also oscillatory strengths were calculated from the absorption spectra. The results were used to compute the radiative properties of Er 3+:CdBiB glasses. The concentration quenching and energy transfer from Yb 3+-Er 3+ were explained. The stimulated emission cross-section, full width at half maximum (FWHM) and FWHM × σpE values are also calculated for all the Er 3+:CdBiB glasses. Copyright © 2011 John Wiley & Sons, Ltd.


Raju C.N.,Sri Venkateswara Degree College | Reddy C.A.,Sri Venkateswara Degree College | Sailaja S.,Sri Venkateswara Degree College | Seo H.J.,Pukyong National University | Reddy B.S.,Sri Venkateswara Degree College
Journal of Materials Science | Year: 2012

This article reports on the optical absorption and NIR emission properties of Nd 3+ ions doped CdO-Bi 2O 3-B 2O 3 (CdBiB) glasses. Judd-Ofelt theory has been applied to calculate the oscillatory strengths of the transitions in the absorption spectra and also the intensity parameters Ω λ (λ = 2, 4, and 6). These results were then used to compute the radiative properties of emission transitions of Nd 3+:CdBiB glasses. From the NIR emission spectra of Nd 3+:CdBiB glasses, three NIR emission bands are observed at 900, 1069, and 1338 nm and assigned to the transitions ( 4F 3/2 → 4I 9/2), ( 4F 3/2 → 4I 11/2), and ( 4F 3/2 → 4I 13/2), respectively. The concentration quenching phenomenon has also been explained. The stimulated emission cross-section and FWHM values were calculated for all the Nd 3+:CdBiB glasses. © 2011 Springer Science+Business Media, LLC.

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