Rare-earth Doped Tellurite Glass Research Articles

Mid-IR Rare Earth Doped Tellurite Glass and Optical Fiber

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Racah Parameter and Nephelauxetic Effect on Er<sup>3+</sup>/Nd<sup>3+</sup> Codoped Lithium Niobate Tellurite Glass

The modification of absorption characteristics in rare-earth doped tellurite glasses is important in photonics application. The Er3+/Nd3+ doped glasses of the form (69-x)TeO2-15Li2CO3-15Nb2O5-1Er2O3-(x)Nd2O3 with x= 0.4, 0.8 and 1.0 mol % are successfully made by using conventional melt-quenching technique. Physical properties such as polaron radius, interionic distance, field strength and average distance between acceptors and donors are determined. The absorption spectra reveal eleven prominent peaks centered at 6535.9 cm-1, 10245.9 cm-1, 11415.5 cm-1, 12437.8 cm-1, 13369.0 cm-1, 15267.2 cm-1, 15949.2 cm-1, 17127.1 cm-1, 19084.0 cm-1, 20449.9 cm-1 and 22271.7 cm-1 which corresponding to the transitions from ground state to various states of Nd3+ ions. The crystal field site increases from 8.120 to 8.169 cm-1 due to increase in contraction of Nd3+-ligand. The nephelauxetic function, increase 0.104 to 0.107. The increasing in value describes, the increasing in ionic bond from-0.0004 to-0.0011. The increment in exhibits the increase in the number of effective positive charge connected to neodymium atom and attracts the electrons from ligands as it increases from 1.0004 to 1.0011. These present glass shows the potential candidate of broadband amplifiers and lasers as it is comparable with other Nd3+ doped another host.

The Effect of Nd<sup>3+</sup> Composition on Judd-Ofelt Analysis of Lithium Niobate Tellurite Glasses Codoped with Er<sup>3+</sup>

The modification of absorption characteristics in rare-earth doped tellurite glasses is important in photonics application. The Er3+/Nd3+ doped glasses of the form (69-x)TeO2–15Li2CO3–15Nb2O5–1Er2O3 -(x)Nd2O3 with x =0.2 and 0.6 mol% are successfully made by using conventional melt-quenching technique. The Judd-Ofelt analysis is to determine the local structure and bonding in the vicinity of rare-earth ions. The oscillator strengths are calculated from the absorption spectra and used to evaluate Judd-Ofelt intensity parameters (Ωλ, λ=2, 4 and 6). The values of Ω4 and Ω6 change with the increase of Nd3+ concentration is ascribed to the change in glass network structures. The values of Ω2 are increased from 1.53 to 37.13 (10-22) cm2 with the increase of Nd3+ concentration which indicate an increase in the covalent nature of Nd-O bond and less centrosymmetrical the ion sites. The decrease in τrad for each level with the increase of Nd3+ concentration signifies on how fast a particular level gets depopulated. The values of β for the transitions 4G5/2, 2G7/2 → 4I9/2, 2H11/2 → 4I9/2 and 4F9/2 → 4I9/2 are found to lie in between 99.6 to 100.0%.

Portable optical fiber probe for in vivo brain temperature measurements.

This work reports on the development of an optical fiber based probe for in vivo measurements of brain temperature. By utilizing a thin layer of rare-earth doped tellurite glass on the tip of a conventional silica optical fiber a robust probe, suitable for long-term in vivo measurements of temperature can be fabricated. This probe can be interrogated using a portable optical measurement setup, allowing for measurements to be performed outside of standard optical laboratories.

Optical Investigation of Erbium Doped Lead Tellurite Glass: Judd-Ofelt Analysis

Understanding the absorbance characteristics in topically important rare earth doped tellurite is the issue. The characterizations of optical properties of these glasses are very important for the optimization and nanophotonic applications. The superior nonlinear optical properties, low phonon cutoff, and high quantum efficiency amongst many other characteristics make them promising for potential applications. All of these considerations comprise a powerful control feature for the fabrication of rare-earth doped tellurite glass. In the present work, the absorbance effects of Er3+ doped tellurite glasses synthesized by melt-quenching technique have been investigated. The measured absorption spectra were analysed by Judd-Ofelt. Our findings may provide some useful information towards the development of functional glasses.

Spectroscopic and luminescence characteristics of erbium doped TNZL glass for lasing materials

Rare earth-doped tellurite glasses are very attractive materials for laser and photonic applications, such as optical amplifiers. They have a good glass stability which leads to an enhancement of the radiative transition. In the present study, a new transparent bulk glass with the composition 85TeO2–5Nb2O5–5ZnO–5LiF doped with 1% Er2O3 (TNZL doped with Er3+) was prepared by using the conventional melt-quenching method. The thermal stability and the crystallization behavior of the glass were investigated using Differential Scanning Calorimetry (DSC), X-ray diffraction and Raman spectroscopy. Furthermore, UV–vis–NIR spectra were determined. From these Judd–Ofelt parameters, Ωk (k=2, 4, 6) of Er3+ were evaluated. The oscillator strength type transition probabilities, spectroscopic quality factors, branching ratio and radiative lifetimes of several excited states of Er3+ were predicted using intensity Judd–Ofelt parameters. The down conversion, up conversion and near infrared luminescence of the Er3+ ions in TNZL glass were investigated. Green and red emissions corresponding to (2H11/2, 4S3/2)→4I15/2 and 4F9/2→4I15/2 transitions were observed.

Judd Ofelt Analysis and Optical Properties of Rare Earth Doped Tellurite Glasses

In this work, the structural characteristic and photoluminescence properties were investigated in Eu\(^{3 + }\) ions-doped B\(_{2}\)O\(_{3}\)-TeO\(_{2}\) --ZnO-Na\(_{2}\)O glasses. These glasses were prepared by the melting method in air, after that thermal annealed 350\rc{}C, 450\rc{}C and 550\rc{}C for different times. The analysis results of structure on these glasses showed the formation of micro-crystals in host glass after thermal annealed process. The photoluminescence spectra of Eu\(^{3 + }\) ions in these samples were observed. The local vibration mode around Eu\(^{3 + }\) ions was investigated by the phonon side band associated with \(^{7}\)F\(_{0}\)- \(^{5}\)D\(_{2}\) transition of Eu\(^{3 + }\). Judd-Ofelt parameters have been evaluated from photoluminescence spectra and were to predict the luminescence intensity ratios of \(^{5}\)D\(_{0} \to ^{7}\)F\(_{J}\) (J=2, 4 and 6) to \(^{5}\)D\(_{0} \to ^{7}\)F\(_{1}\) transition. The obtained results have been used for calculating \(\Omega_{2}\), \(\Omega _{4}\), \(\Omega _{6}\) parameters by using Judd-Ofelt theory. These \(\Omega _{2}\), \(\Omega _{4}\), \(\Omega _{6}\) parameters allow to derive radiative properties of Eu\(^{3 + }\) ions in glass material such as transition probabilities, radiative lifetimes and peak stimulated emission cross-section for the \(^{5}\)D\(_{0} \to ^{7}\)F\(_{J}\) transitions.

Optical Absorption of Nd<sup>3+</sup> Doped Tellurite Glass Containing Ag Nanoparticles

Understanding the optical properties of rare earth doped tellurite glasses with embedded metallic nanoparticles (NPs) are promising for photonics. Series of Nd3+ doped tellurite glasses containing Ag NPs having chemical composition (70-x)Te2O3-10MgO-20Li2CO3-0.5Nd2O3-xAg, where 0.0 x 1.0 mol% are synthesized. Their optical properties are measured using UV-Vis-NIR spectroscopy. The absorption spectra exhibits nine absorption bands in the wavelength range of 300-900 nm are obtained and the glass showed light emission due to 4F3/2 4I9/2 transition. The values of optical band gap Eopt and Urbach energy Eu are evaluated from the absorption band. The value of Eopt is found to lie between 2.78 and 2.91 eV for the direct transition whereas the Eu values lie between 0.27 and 0.37 eV. The optical behavior of the samples is studied with varying Ag NPs content and the results are compared with similar studies.

Concentration dependent luminescence quenching of Er3+-doped zinc boro-tellurite glass

Understanding the mechanism of luminescence quenching in rare earth doped tellurite glass is an important issue. The Er3+-doped boro-tellurite glasses with compositions 30B2O3+10ZnO+(60−x)TeO2+xEr2O3 (where x=0, 0.5, 1, 1.5 and 2mol%) were prepared by melt quenching method. Structural and optical properties of the proposed glasses were characterized using XRD, FTIR, density, UV–vis-IR absorption and PL spectroscopy. The amorphous nature of these glasses was confirmed by XRD technique. The IR-spectrum reveals five absorption bands assigned to different B–O and Te–O vibrational groups. UV–vis-IR absorption spectrum exhibits seven absorption bands at 6553, 10,244, 12,547, 15,360, 19,230, 20,661 and 22,522cm−1 corresponding to 4I13/2, 4I11/2, 4I9/2, 4F9/2, 2H11/2, 4F7/2 and 4F3/2 excited states of Er3+ ion respectively. The optical band gap energy (Eopt) corresponding to the direct and indirect allowed transitions decreased, while the Urbach energy and cut-off wavelengths are increased by the introduction of Er3+ ions. The refractive index, density and phonon cut-off edge of the samples are increased and the molar volume decreased with the further addition of dopants. The Judd–Ofelt parameter (Ω2) decreased from 5.73 to 3.13×10−20cm2 with the increase of erbium ions concentration from 0.5 to 2mol%. The PL spectra show green emissions for the transition from 2H11/2 and 4S3/2 excited states to 4I15/2 ground state, which show strong quenching due to the addition of Er3+ ions.