Doped Tellurite Glasses Research Articles

Enhanced gain bandwidth of Tm3+ and Er3+ doped tellurite glasses for broadband optical amplifier

In this work, (90-x-y)TeO2-10GeO2-(x)Tm2O3-(y)Er2O3 composition of germano-tellurite glasses were synthesized by traditional melting and quenching technique and the spectroscopic properties of synthesized glasses were investigated. The values of Judd-Ofelt (JO) intensity parameters (Ωt(t = 2,4,6)), spontaneous transition probabilities (Α), branching ratios (β) and radiative lifetimes (τR) were obtained by using the Judd-Ofelt (JO) theory and absorption spectra. The stimulated emission cross-sections of TG:Tm and TG:Er glasses in 1.47 μm and 1.53 μm wavelength regions were calculated by Füchtbauer-Ladenburg formula and McCumber theory, respectively. The gain bandwidth-cross section product of TGTm0.5 and TGEr1 glasses was found to be 445.76 × 10−28 cm3 and 849 × 10−28 cm3, respectively. The fluorescence lifetime measurements were done for the 3F4 and 4I13/2 levels to compare with the radiative lifetimes. These results suggest that the TG:Tm and TG:Er studied glasses can potentially possess wider gain bandwidth for S-band amplifier and broadband optical amplifier WDM at 1.53 μm, respectively.

Upconversion properties of erbium nanoparticles doped tellurite glasses for high efficient laser glass

Erbium nano particles (NPs) doped tellurite glasses were prepared via melt-quenched technique and their chemical composition are as follows; {[(TeO2)0.70 (B2O3)0.30]0.7(ZnO)0.3}y (Er2O3NPs)1−y, y = 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05. The amorphous state of the glass system was revealed and the structural parameters indicating the formation of non-bridging oxygen was shown. The current work underlines the spectral parameters from Judd–Ofelt (JO) studies, and upconversion spectra. The existence of erbium NPs was found experimentally using transmission electron microscopy (TEM). The Judd–Ofelt analysis suggests that the radiative probability, Arad is strong at 2H11∕2 —>4I15∕2 and a longer lifetime at 4I11∕2 —>4I15∕2. The Argon laser beam was used to determine the upconversion emission peaks. The upconversion radiation emission excited at 800 nm was found in the range 390 nm.

Thermal and nonlinear optical properties of Tm3+-doped tellurite glasses

In the present work, thermal and nonlinear properties of tellurite glasses doped with Tm2O3 were investigated by means of thermal lens, thermal relaxation and z-scan measurements. The composition of the samples was (78 − x) TeO2 + 4.5 Bi2O3 + 5.5 ZnO + 10.5 Li2O + 1.5 Nb2O5 + xTm2O3 (x = 0.05, 0.1, 0.5, 1.0 and 1.5 mol%). Thermal diffusivity (D), specific heat (ρc), thermal conductivity (K) and optical path change with temperature (ds/dT) were determined as a function of Tm3+ concentration. Concerning thermal–optical properties, our results show that the 0.5 mol% Tm doped is the most suitable sample for laser applications as it presented the lowest ds/dT and highest thermal diffusivity (conductivity). Third-order nonlinearities were observed and discussed in 1.0 and 1.5 mol% samples. The nonlinear indices (n2) found were 1.16 × 10−13 and 3.89 × 10−13 cm2 W−1, respectively. The data obtained show that the Tm3+-doped TBZLN glasses have potential for future opto-electronic devices.

Dy3+ doped tellurite glasses for solid-state lighting: An investigation through physical, thermal, structural and optical spectroscopy studies

In the present work, a series of Dy3+ ion doped tellurite glasses in the (50-x)TeO2-25WO3-25Li2O-xDy2O3 system were synthesized using conventional melt quenching technique to investigate colorimetric and radiative properties of Dy3+ ions in a new and stable host for their evaluation as solid-state lighting materials. Physical and structural properties were studied through density calculations, refractive index measurements, and Fourier-transform IR spectroscopy analysis. Thermal properties of glasses – glass transition (Tg) and crystallization (Tc/Tp) temperatures and temperature difference (ΔT) – were determined using differential scanning calorimetry. Optical absorption spectra of glasses were recorded with Vis-NIR spectrophotometer. CIE color coordinates, correlated color temperature, color rendering index and yellow to blue emission intensity ratio values were obtained through photoluminescence analysis. Radiative properties such as, radiative transition probability, stimulated emission cross-section, branching ratio and optical bandwidth gain were calculated according to Judd-Ofelt theory. The obtained optical spectroscopy results were found to be comparable or better than other reported glass systems. From the derived results, glasses with Dy3+ ion concentration lower than 0.5 mol% were found to show the closest CIE color coordinate values to pure white light and highest CCT and CRI values revealing good potentiality to be used for applications in white LEDs and solid-state lasers.

Spatially resolved X-ray fluorescence, Raman and photoluminescence spectroscopy of Eu3+/Er3+ doped tellurite glasses and anti-glasses

Strontium tellurite, lead tellurite and bismuth niobium tellurite glasses containing 1 to 2 mol% of Eu3+ and Er3+ were prepared by melt-quenching and found to contain anti-glass inclusions (droplet phase) of size of several micrometers. Anti-glasses are disordered crystals that have long-range order of the cations such as Sr2+, Pb2+, Bi3+, Nb5+ and Te4+ but have a disordered arrangement of the anions (O2−), therefore these materials exhibit sharp peaks in the X-ray diffraction patterns due to the long range cationic order but the Raman spectra show broad bands due to the vibrational disorder. The glass matrix and anti-glass inclusions in the samples were characterized by synchrotron micro-X-ray Fluorescence (XRF), Raman and photoluminescence mapping studies. The XRF line analysis confirmed that the anti-glass and glass matrix phases have equal concentration of metal ions. The samples containing Eu3+ show intense red photoluminescence at an excitation wavelength of 375 nm, while Er3+ doped samples exhibit strong green emission by the up-conversion of infrared photons (980 nm). The spatially resolved XRF, Raman and photoluminescence spectroscopy found that the inclusions and the glass matrix have the same metal ion concentration, short-range order, TeO speciation and the light emission properties.

Enhanced fluorescence emission of 2.7 μm from high thermal stability Er3+/Bi3+co-doped tellurite glasses for mid-infrared lasers

2.7 μm fluorescence of Er3+ single doped glass and Er3+/Bi3+ co-doped glasses are obtained when excited by a 980 nm laser diode. The fluorescence emission intensity from Er3+ is enhanced significantly by doping Bi3+ in tellurite glass. In comparison with the single doped Er3+, the emission intensity increased by 17.8%. The measured parameter ΔT(154.8℃)＞130 ℃ indicates that compared with Er3+/Nd3+ co-doped tellurite glass and Tm3+ doped lead silicate glass, there is a better resistance to crystallization and thermal performance in Bi3+ doped tellurite glass. The enhanced 2.7 μm fluorescence emission of sample with the introduction of Bi3+, which may be caused by energy transfer between Bi3+ and Er3+.Above all, Strong 2.7 μm emission and good thermal properties reveal that the Bi3+/Er3+ co-doped glass may be a potential material to improve 2.7 μm laser performance of Er3+.

Fabrication of tellurite glass microdisks with thermal pressing method

In this work, we report a two-step thermal pressing method of fabricating microdisk lasers that are suitable for processing thermally stable glass materials, and we utilize a tellurite glass (TeO<sub>2</sub>-ZnO-Na<sub>2</sub>O) to demonstrate the feasibility of this method. Compared with the conventional microdisk fabricating methods that rely on a series of complicated procedures, such as lithography, etching, thermal reflow, and ion implantation, this thermal pressing method involves only two heating procedures and can be accomplished with simple laboratory resistive heating furnaces. In the first heating procedure, we crush bulk tellurite glass into powders and drop those powders through a vertical heating furnace. Glass powders are transformed into microspheres by surface tension in the furnace. In the second heating procedure, microspheres are placed between two flat/smooth surfaces and are thermally treated when being pressed with suitable weights. With this procedure, the “flattened” microspheres turn into the microdisks. In this work, we demonstrate that our fabricated tellurite glass microdisks possess diameters of 100－400 μm, thinnest thickness of ～ 8 μm, and typical quality-factor (<i>Q</i>-factor) of ～ 10<sup>5</sup>. We also dope tellurite glass with active dopants such as Nd<sup>3+</sup> and Tm<sup>3+</sup> to fabricate the active microdisk resonators. We couple those active microdisk resonators with fiber tapers and demonstrate that with appropriate pump power, apparent fluorescence whispering gallery mode and laser mode can be obtained. Taking a 105.74-μm-diameter, 10.4-μm-thickness, and Nd<sup>3+</sup>-doped tellurite glass microdisk for example, we show that as the pump power increases above a threshold of 1.364 mW, a lasing peak near 1.06 μm can be obtained. We also show that lasing peaks near 1.9 μm can be obtained by coupling/pumping Tm<sup>3+</sup> doped microdisks.

Erbium 1.55μm luminescence enhancement due to copper nanoparticles plasmonic activity in tellurite glasses

Abstract The effect of copper nanoparticles (CuNP) on the enhancement of the infrared and upconversion emissions intensities in the Er3+/Yb3+/Ce3+ co-doped transparent tellurite glasses under 980 nm laser diode excitation were investigated. The roles of Yb3+ and Ce3+ as sensitizers are also discussed. The nanoparticles-containing tellurite glasses structures were characterized by Differential Scanning Calorimetry (DSC) and X-ray diffraction (XRD) measurements. The presence of the CuNP was confirmed by Transmission Electronic Microscopy (TEM) images. Also, the optical investigation of the glasses was performed by absorption and luminescence spectra, upconversion emission and luminescence lifetimes. The effectiveness of localized surface plasmon resonance (LSPR) of the CuNP provides an improvement about 47% of the infrared luminescence intensity. Moreover, the lifetime of 4I13/2 Er3+ energy level increased around 50% in the CuNP-containing samples. Thus, the Er3+/Ce3+/Yb3+-doped tellurite glass containing CuNP is suitable to be used in infrared optical devices.

Optical investigation of Er3+ and Er3+/Yb3+ doped zinc-tellurite glass for solid-state lighting and optical thermometry

Er3+ and Er3+/Yb3+ doped zinc tellurite (ZnO/TeO2) glasses were prepared using melt quenching technique. Spectroscopic properties of the glasses were studied by absorption spectroscopy, luminescence spectroscopy, and color chromaticity coordinates (CIE-1931) measurements. Upconverted-emission intensities and the CIE-1931 coordinates were strongly affected by the presence of Yb3+ ion, as well as the excitation power density of 975 nm laser light. Effect of temperature on green upconverted-emissions from two thermally coupled 2H11/2 and 4S3/2 levels of Er3+ ions were measured and fluorescence intensity ratio technique was applied to investigate the temperature sensing properties. High sensitivity and short response time properties make ZnO/TeO2 glasses a very good candidate for non-contact optical temperature sensor applications. The maximum sensitivity of the glasses doped with Er3+ and Er3+/Yb3+ were found to be 72 × 10−4 K-1 and 120 × 10−4 K−1 at 429 K, respectively which are much higher than previously reported temperature sensors based on Er3+ ion doped materials. Hence, Er3+/Yb3+ doped zinc-tellurite glass can be more suitable than that of doped with Er3+ ions only for color tunable solid-state lighting and non-contact optical thermometry applications.

2.3 µm laser action in Tm3+-doped tellurite glass fiber

A 2.3 µm laser action, as well as a cascade 2.3 µm and a 1.9 µm lasing in a diode-pumped tellurite glass fiber, is demonstrated for the first time.

Rare-earth ions doped zinc-tellurite glass for 2 ÷ 3 µm lasers

High-purity and well-dehydrated (hydroxyl absorption at 3.3 µm no more than 0.02 cm−1) rare-earth ions doped glasses of ZnO–TeO2 system were synthesized. The luminescent properties of Tm3+, Er3+, Ho3+ and Dy3+ ions were investigated in the prepared glass samples. The performed investigations had shown that zinc-tellurite glass is quite a promising host for 2.3 µm Tm3+ and 2.7 µm Er3+ lasers. Pulsed 2.3 µm laser action with output energy up to ~ 12 mJ was demonstrated in bulk Tm3+ doped tellurite glass. The losses in the fiber made of Tm-doped glass were not exceeding 0.8 dB/m (~ 2 × 10−3 cm−1) in the spectral range of 2.1/2.7 µm.

Luminescent properties of Eu3+ doped heavy tellurite scintillating glasses

Eu3+ doped tellurite scintillating glasses were prepared by the conventional melt-quenching method. The physical and luminescent properties of glasses were investigated by DTA, density, transmittance spectra, photoluminescence spectra, and X-ray excited luminescence (XEL) spectra. The densities of the glasses are in the range from 5.89 g/cm3 to 6.05 g/cm3. The glasses exhibit intense red emissions upon 393 nm light and X-ray excitations. The maximum integral XEL intensity of the glasses is about 6% of that of commercial Bi4Ge3O12 (BGO) scintillating crystal. The results reveal that Eu3+ doped tellurite glass could be a scintillator candidate used in X-ray detection field.

Visible light emission from Dy3+ doped tellurite glass: Role of silver and titania nanoparticles co-embedment

We report the influence of silver (Ag) and titania (TiO2) nanoparticles (ATNPs) co-embedment on the photoluminescence (PL) properties of dysprosium ions (Dy3+) doped zinc-magnesium tellurite glass system prepared using conventional melt quenching method. Both up- and down- converted PL spectra of glasses revealed three emission bands located at 482 (blue: 4F9/2 → 6H15/2), 574 (yellow: 4F9/2 → 6H13/2) and 664 nm (weak red: 4F9/2 → 6H11/2), where the band intensities were enhanced with the inclusion of ATNPs. Glasses with 0.2 mol% of ANPs and up to 0.3 mol% of TNPs disclosed highest PL intensity enhancement, which was majorly attributed to the ATNPs mediated localized surface plasmon resonance (LSPR) and large field enhancement (called hot spot) effects in the proximity of Dy3+ ions. Absorption spectra of glasses displayed two plasmon bands characteristics of each type of nanoparticle. It was inferred that the superposition of localized SP modes from ATNPs could generate new hybridized modes (strong local field in the vicinity of Dy3+ ions) shifted with respect to the single type of NPs resonance. HRTEM images showed the existence of both Ag and titania NPs inside the glass matrix. Glasses containing ATNPs exhibited anatase phase with (103) and (112) nanocrystalline lattice plane orientation. Proposed glass system may be useful for the development of solid state laser and photonic devices.

Suitable Er3+-doped tellurite glass-based plasmonic structures for nanophotonic device applications

The excitation and emission obtained from an Er3 + -doped tellurite glass with embedded silver nanoparticles (SNPs) through nanostructured surfaces consisting of a square lattice of nanoholes (squares or circles) in a silver thin film are addressed. The periodic nanostructures were fabricated with a focused gallium ion beam on a silver thin film deposited onto an Er3 + -doped tellurite glass with embedded SNPs. The Er3 + microluminescence spectra were measured in the far field (510- to 590-nm wavelength range). The emission observed through the plasmonic nanoholes is caused by the excitation of the Er3 + ions via extraordinary optical transmission from the periodic nanostructures. Two coupling types are proposed: (i) one between the SNPs and the Er3 + ions (electric dipole type) and (ii) a resonant coupling between the SNPs (localized surface plasmon resonance) and a silver thin film (surface plasmon polariton). These two couplings modify the local field, which improves the emission intensity of Er3 + . A dependence of the intensity emission with the geometrical shape of the nanoholes and the number of elements of the square lattice was observed. These findings can be very useful for nanophotonic device applications employing a transparent medium with optical gain.

Color tuning of YAG:Ce3+ phosphor-in-glass nanocomposites using a Sm3+ doped tellurite glass

Color tuning of YAG:Ce3+ phosphor-in-glass nanocomposites using a Sm3+ doped tellurite glass

Broadband near-infrared luminescence at around 1.0 µm in Pr3+/Er3+ co-doped tellurite glass

In this work, the near-infrared band photoluminescence properties around 1.0 µm in Pr3+/Er3+ co-doped tellurite glass was investigated. The doped tellurite glass with composition TeO2-WO3-ZnO-La2O3 was synthesized using melt-quenching technique and characterized by UV/Vis/NIR absorption spectrum, near-infrared emission spectrum, X-ray diffraction (XRD) pattern and Raman spectrum. Under the excitation of 488 nm laser, a broad 1.0 µm band luminescence ranging from 950 to 1100 nm with a full width at half maximum (FWHM) up to 94 nm was observed, nearly two times compared to that in Pr3+ or Er3+ single-doped case. This broadband near-infrared luminescence was contributed by the Er3+:4I11/2 → 4I15/2 and Pr3+:1D2 → 3F4 radiative transitions which lead to two emissions located at 980 and 1040 nm, respectively. The structural analysis of XRD pattern and Raman spectrum proved the long-range structural disorder in synthesized glasses, and based on the absorption spectrum, some important spectroscopic parameters such as the Judd-Ofelt intensity parameter, spontaneous radiative transition probability, fluorescence branching ratio, absorption and emission cross-sections, and gain coefficient spectrum were calculated to reveal the radiative properties of doped tellurite glass. The obtained results indicate that Pr3+/Er3+ co-doped tellurite glass is a promising candidate to fabricate a broadband near-infrared luminescent source for telecommunication and other applications such as medical imaging system.

Temperature dependent upconversion and spectroscopic properties of Nd3+ doped barium bismuth tellurite glasses

This work reports on the spectroscopic properties and temperature dependent NIR to visible upconversion of Nd3+ doped barium bismuth tellurite glasses. Raman spectrum analysis was performed to predict the maximum phonon energy. Spectroscopic parameters (Ω2, Ω4, Ω6 and χ) and radiative properties of certain transitions of Nd3+ ions were calculated by applying Judd–Ofelt (J–O) theory. The concentration dependence of NIR emission and visible upconversion intensities of various levels were discussed. Decrease in the experimental lifetime of Nd3+: 4F3/2 level with increase of Nd3+ ion concentration has also been discussed by analysing decay curves of the NIR emission. The variation of upconversion spectral intensities with respect to sample temperature was studied. Thermal quenching was observed in all the upconversion bands and no anomalous variations were observed in the temperature range 14–300 K.

Gold Nanoparticles Sensitized Samarium Doped Tellurite Glass: Assessment of Structural and Thermal Stability

Gold Nanoparticles Sensitized Samarium Doped Tellurite Glass: Assessment of Structural and Thermal Stability

Highly sensitive and accurate optical thermometer through Er doped tellurite glasses

We investigate the thermal effects of Er3+ doped tellurite glasses on the upconversion properties. It is found that the sensitivity of the thermometer based on the FIR technique increases monotonously with the decreasing doping concentration. However, low doping leads to weak upconversion intensity and further decrease the sensing accuracy, which makes it difficult to achieve the high sensitivity and accuracy simultaneously. Influences of the irradiating laser power on the sensing behaviors were studied in the purpose of enhancing the signal intensity. It is found that the heating effect of incident laser (up to hundreds of mW) can be neglected, indicating the feasibility of using high laser power and low doping sample to produce both high sensitivity and high accuracy. In addition, this paper respectively discusses the mechanisms of the upconversion processes and the concentration dependent sensitivity.

Spectroscopic properties of Dy3+ doped tellurite glass with Ag/TiO2 nanoparticles inclusion: Judd−Ofelt analysis

Silver (Ag) and Titania (TiO2) nanoparticles (ATNPs) co−embedded and dysprosium (Dy3+) ions doped magnesium−zinc−tellurite glasses were synthesized via melt quenching method. As−prepared samples were characterized using various analytical tools. Nanoparticles concentration dependent spectroscopic properties of the prepared glasses were evaluated using Judd−Ofelt (J−O) analysis. XRD pattern verified the amorphous nature of as−quenched samples. The UV–Vis spectra revealed six absorption bands centred at 1690, 1283, 1097, 904, 800 and 755 nm, assigned to the transitions from the ground level to different excited levels of Dy3+ ions. The photoluminescence (PL) emission spectra of the glass system displayed three emission bands positioned at 482 (blue: 4F9/2 → 6H15/2), 574 (yellow: 4F9/2 → 6H13/2) and 664 nm (weak red: 4F9/2 → 6H11/2). For all the bands, the PL intensities of the studied glasses were more pronounced than singly embedded sample (either ANPs or TNPs). Furthermore, the enhancement in the PL peak intensity due to the inclusion of metallic NPs was attributed to the surface plasmon resonance mediated local field effect in the proximity of Dy3+ ions. Ligand bonding of Dy3+ showed the ionic nature of the prepared glasses. The absorption and emission spectral data were used to evaluate the J−O intensity parameters (Ωλ (λ = 2, 4, 6)) and radiative properties. Values of Ωλ (λ = 2, 4, 6) for glass with 0.1 mol% of TNPs exhibited the trend of Ω2>Ω6>Ω4 while all other glasses revealed Ω2>Ω4>Ω6. It was demonstrated that by combining two types of NPs (Ag and TiO2) hot spot with intense electromagnetic field could be created in the neighbourhood of Dy3+ ion to achieve enhanced optical attributes of the proposed glasses. The attainment of large quality factors and quantum efficiency (≈100%) in the ATNPs co−embedded glasses were established to be beneficial for the development of solid state lasers and other photonic devices.