Codoped Tellurite Glasses Research Articles

Enhancing yellow-green emission in Eu/Tb co-doped tellurite glasses controlled by Lu2O3

In this research, Lu2O3 was incorporated into Eu3+ and Tb3+ co-doped tellurite glasses to enhance structural stability and modify the yellow-green emission. A series of microstructural analyses, including Differential Scanning Calorimetry (DSC), Raman spectroscopy, and density measurements, confirmed that the addition of Lu2O3 causes the long-chain or cyclic Te-O-Te network structure to break, resulting in the formation of more [TeO3], which in turn leads to an increase in non-bridging oxygens (NBO) and lowers the phonon energy of the matrix material. Fluorescence spectral characterization revealed that both green and yellow luminescence intensities peaked when Lu2O3 concentration reached 15 %. Additionally, the Judd-Ofelt theory supports its superior laser performance. With the addition of Lu2O3,The radiative transition probability (Arad), lifetime (τrad), and branching ratio (β) of the excited states of Tb3+ and Eu3+ have all been enhanced.Under the regulation of 15% Lu2O3, The maximum absorption cross-section of at 544 nm is 1.88×10-20 cm2, and the maximum emission cross-section is 2.14×10-20 cm2. At 611 nm, the maximum absorption cross-section is 1.05×10-20 cm2, and the maximum emission cross-section is 1.44×10-20 cm2. The decay curve indicates a fluorescence lifetime enhancement from 0.6 ms to 1 ms with Lu2O3. These results underscore the potential of Lu2O3 modulated Eu3+/Tb3+ co-doped tellurium glass as an effective yellow-green laser gain medium.

Properties of Gamma Ray Shielding Ho/Nd Codoped Tellurite Glasses

Properties of Gamma Ray Shielding Ho/Nd Codoped Tellurite Glasses

Enhanced upconversion luminescence of Er3+/Y3+ co-doped tellurite glasses for volumetric three-dimensional display

Large-sized Er3+/Y3+ co-doped tellurite glasses with high image quality were prepared by a conventional melt-quenching method for volumetric three-dimensional display. The effects of the concentration of Er3+ and Y3+ on the two-frequency upconversion luminescence properties and volumetric three-dimensional display were investigated. Under dual-wavelength excitation at 850 nm and 1550 nm, the two-frequency two-step upconversion luminescence intensity at 546 nm in the Er3+/Y3+ co-doped tellurite glass was significantly enhanced by about 44% compared with that in the Er3+ doped tellurite glass. However, the upconversion luminescence mechanism and its dynamic process were further obtained. A range of the high-resolution and high-contrast volumetric three-dimensional images can be achieved in the Er3+/Y3+ co-doped tellurite glass with optimal doping concentration, utilizing a coordinated control system of galvanometer scanner and digital micro-mirror devices. The results indicate that Er3+/Y3+ co-doped tellurite glass has promising potential for widely volumetric 3D displays.

Stokes and anti-Stokes emission characteristics of Er3+/Yb3+ co-doped zinc tellurite glasses under 377 and 1550 nm excitations for solar energy conversion application

One of the best rare earth combinations for down- and up-converting the solar photons is Er3+/Yb3+. Therefore, at present, by using the traditional melt quench technique, zinc tellurite glasses doped with Er3+ and Er3+/Yb3+ were characterised. Several methods of down-conversion that result in the emission of 1000 nm from the acceptor (Yb3+) under excitation of donor (Er3+) were studied. On the other hand, the impact of acceptor (Yb3+) concentration and excitation pump power on the excited state absorption and its influence on the up-conversion emission (1000 nm) properties were investigated in detail under 1535 nm excitation. The studies on emission and decay results are discovered to be very significant. Suggesting that these glasses when used as conversion layers, can append the conversion efficiency of Si-based solar cells.

A composite photoluminescent probe based on Er/Yb co-doped tellurite glass powder for dual-parameter measurement of temperature and UV radiation

To cope with the cross-sensitivity of simultaneous measurement of ultraviolet (UV) irradiance and temperature, we propose and experimentally demonstrate a miniature composite photoluminescent probe that is formed by thoroughly mixing Er/Yb co-doped tellurite glass powder into a resin adhesive substrate. Utilizing tellurite glass in form of powder not only guarantees its thorough mixing into the liquid resin base, but also retains its amorphous glass phase for hosting Er/Yb ions, thus breaking the limitations of studying tellurite glass only in bulk or fibrous form. Co-excited by UV radiation and NIR pumping, the composite probe produces a superimposed fluorescence emission spectrum, where the intensity change rate of the 488 nm dip can be used for UV irradiance measurement, and the fluorescence intensity ratio (FIR) of the 524 nm and 545 nm peaks for temperature measurement. Based on the sensitive specificity of the resin substrate and the Er/Yb co-doped tellurite glass, we have realized the simultaneous measurement of UV and temperature without cross-sensitivity.

Nonlinear optical properties in Pr3+-Er3+-codoped tellurite glasses

In this investigation, we systematically probe the structural, optical, and, notably, the nonlinear optical properties of Pr3+-Er3+-codoped tellurite glasses to understand the potential new functionalities of the glass and, thus, their applicability. The glass samples were synthesized employing the melt-quenching technique and subsequently characterized using X-ray photoelectron spectroscopy (XPS) and femtosecond (fs) pulse Z-scan measurements at 720 and 750 nm wavelengths. XPS analyses unveiled increased non-bridging oxygens (NBO) with ascending Pr2O3 content. It was observed that the increasing concentrations of Pr3+ ions show a linear dependence with the increase of NBO in the glass network (r2 > 0.95). This trend further supported the formation of Te3+ ions via the oxidation of Te4+ for charge compensation and was affirmed by a decrement in average TeO bond as Pr2O3 concentrations increased. The tellurite glasses showcased positive nonlinear refraction on the nonlinear optical (NLO) front. The rise in n2 values was directly linked to the Pr2O3 content, a phenomenon attributed to the increased presence of non-bridging oxygens and the inherent polarizability of Pr3+ ions. Collectively, our findings offer pivotal insights into the modulation of NLO attributes in Er3+-doped tellurite glasses via Pr3+ ion doping, underscoring their potential in advanced NLO device applications.

Ag nanoparticles enhanced 3.1 μm mid-infrared emission of Er3+/Bi+ co-doped oxyfluoride tellurite glasses

Ag nanoparticles enhanced 3.1 μm mid-infrared emission of Er3+/Bi+ co-doped oxyfluoride tellurite glasses

Effective enhanced 3.1 μm mid-infrared emission of Er3+/Yb3+ co-doped tellurite glasses introduced Ag nanoparticles

Effective enhanced 3.1 μm mid-infrared emission of Er3+/Yb3+ co-doped tellurite glasses introduced Ag nanoparticles

Improving 2–4 μm mid-infrared fluorescence properties of Ho3+ via Er3+ energy transfer in tellurite glasses

Despite significant advancements in the field of mid-infrared lasers, the fluorescence around the 2–4 μm wavelength range remains a pressing concern. Ho3+/Er3+ co-doped TeO2–ZnO–Nb2O5–PbO (TZNP) glasses were fabricated by conventional melt-quenching technique, and we also characterized their excellent mid-infrared (MIR) fluorescence properties. According to the observed parameter ΔT (144–141 °C) > 120 °C from differential scanning calorimeter (DSC) curves, the manufactured tellurite glass specimens displayed enhanced thermal stability and crystallization resistance. X-ray diffractometer (XRD) images demonstrated the non-crystalline structure of the produced specimens. Ho3+/Er3+ co-doped tellurite glass specimens achieved emission enhancements of 2.0 μm and 4.1 μm through energy absorption of 980 nm LD, which could be assigned to the Ho3+: 5I7 → 5I8 and Ho3+: 5F5 → 5I4 radiation transition processes respectively. Meanwhile, intense 3.1 μm fluorescence was observed, which could be attributed to the transition of Er3+: 4S3/2 → 4F9/2. We investigated the fluorescence properties of the produced glasses in detail, and the processes of energy transferring between Ho3+/Er3+ were discussed on the basis of the quenching and increasing emission intensity at different dopant proportions of Er3+ ions. Additionally, the optimized 1 mol% Ho3+ and 1.5 mol% Er3+ co-doped TZNP glass possessed the strongest emission intensity, and the fluorescence lifetime values of this sample were calculated to be 1.81 ms and 1.38 ms at 2.0 μm and 4.1 μm, respectively. The gain coefficients demonstrated that only small pump energy can achieve the MIR laser gains. These above findings suggest that the prepared samples are potentially competitive and efficient as an innovative glass in the MIR laser design and optical amplifiers applications.

Down-/Up-conversion luminescence behaviors and energy transfer analysis in Tm3+ and Tm3+/Yb3+ co-doped tellurite glasses

Glasses with the chemical composition of (50-x-y) TeO2-30ZnO-10YF3-10NaF-0.5Tm2O3-yYb2O3 (y = 0.5, 1.0, and 3.0 mol%) are developed using a melt-quenching method. Measurements of absorption, excitation, down and up-conversion emission spectra, and decay times were used to investigate the energy transfer processes. Cross-relaxation mechanisms caused the emission intensity to decrease at higher Tm3+ ion concentrations. The Tm3+/Yb3+ co-doped glasses showed strong up-conversion emission under the diode laser excitation at 978 nm. Studies on the dependence of pump energy revealed the mechanism underlying the up-conversion luminescence. According to the findings, the developed Tm3+/Yb3+co-doped glasses are also found to be a promising option for spectral conversion and emission (visible and near infrared) applications.

A ratiometric fluorescent fiber sensor based on integrated silica and tellurite glass for real-time human thermal monitoring

In this paper, we propose and demonstrate a portable fiber sensor with integrated tellurite and silica for dynamic human thermal monitoring, where Er3+/Yb3+ co-doped tellurite glass is employed to generate upconversion fluorescence emission related to thermally coupled energy levels via near-infrared excitation for ratiometric thermometry. The molten tellurite glass is extracted into a silica tube using the negative pressure approach, allowing for intimate adhesion between different glass materials with considerable softening temperature differences. With a fast instantaneous response of 0.4–0.6 s and an absolute error of −0.45–0.36 K, the sensor can accurately and timely capture small temperature fluctuations. The sensor is placed in the mouth or attached to the hand skin to measure the body temperature continually. It is also positioned in the mouth exhalation and nose breathing environments to monitor thermal activities in real-time, offering a new, highly reliable method for human health monitoring.

Broadband 2.9 μm and 4.1 μm mid-infrared emission and energy transfer mechanisms in Ho3+/Yb3+ co-doped tellurite glasses

Broadband 2.9 μm and 4.1 μm mid-infrared emission and energy transfer mechanisms in Ho3+/Yb3+ co-doped tellurite glasses

A systematic interpretation of the quantum cutting effect by a cooperative energy transfer mechanism in Te4+/Yb3+ co-doped tellurite glasses

The near-infrared downconversion (DC) mechanism in Te4+/Yb3+ co-doped 75TeO2–25Li2O tellurite glasses (amounts in mol%) was closely followed using optical and thermal spectroscopy techniques. The glasses were prepared by the conventional melt-quenching method, with a melting temperature of 800 °C, in an ambient atmosphere, which were the best synthesis conditions for observing Te4+ in the glass. The results indicated that excitation in the ultraviolet region led to an intense emission of two NIR photons (at around 978 nm) in the co-doped tellurite glasses. This effect revealed the occurrence of a cooperative energy transfer (CET) mechanism in the system, where a Te4+ ion was responsible for the excitation of two Yb3+ ions. The CET efficiency (ηCET) was calculated from the Te4+ lifetime, obtaining a maximum of 74% for the tellurite glass prepared with the highest Yb3+ concentration. The use of thermal lens spectroscopy confirmed the quantum cutting effect, by observing the dependence of the thermal properties of the glass on the Yb3+ concentration. A maximum DC efficiency of 137% was measured for the sample with 4 mol% of Yb3+.

Fluorescence and Physical Properties of Tm3+/Ho3+ Co-Doped Tellurite Glasses for Mid-Infrared Laser

In this work, a series of Tm3+/Ho3+ co-doped tellurite glasses were successfully prepared by the melt-quenching method. The spectroscopic properties around 2 μm of Tm3+/Ho3+ co-doped tellurite glasses were studied under 808 nm laser excitation. Based on the Judd-Ofelt theory, the phenomenological intensity parameters Ω t (t = 2, 4, 6) of the Tm3+/Ho3+ co-doped tellurite glasses were calculated. In addition, the emission cross-section and the gain coefficient of Ho3+ were calculated, and the maximum values are 0.76 × 10−20 cm−1 and 1.38 cm−1, respectively. These results portend that the Tm3+/Ho3+ co-doped tellurite glass has excellent spectroscopic properties and attractive laser performance in mid-infrared waveband.

Down conversion and efficient NIR to visible up-conversion emission analysis in Ho3+/Yb3+ co-doped tellurite glasses

A series of glasses with chemical composition (50−x−y) TeO2–30ZnO–10YF3–10NaF–xHo2O3–yYb2O3 (x=0.5 and y=0.5, 1.0, 3.0, 5.0mol%) were prepared by melt-quenching procedure. The absorption spectra, excitation, down conversion emission spectra, up-conversion (UC) emission spectra and decay time measurements were analyzed. In down conversion, the visible emission transition intensity associated with 5F4→5I8 (547nm), 5F5→5I8 (657nm), and 5F4→5I7 (755nm) of Ho3+ ions decreased with Yb3+ concentration due to the energy transfer (ET) process from Ho3+ to Yb3+ ions. In up-conversion, on exciting with 980nm diode laser beam, we observed a strong green (543nm) and red (657nm) UC emissions, that refers to the energy level transitions; 5F4 (5S2)→5I8 and 5F5→5I8 of Ho3+. The influence of excitation power on UC intensities studies revealed that the population at 5F4 (5S2) and 5F5 levels of Ho3+ ion occurs due to two-photon absorption process associated energy transfer from Yb3+ to Ho3+. The influence of Yb3+ doped concentration on UC was studied, and it is observed that both the green and red UC intensities improved significantly on increasing Yb3+ ions concentration.

Enhanced Emission of Tellurite Glass Doped with Pr3+/Ho3+ and Their Applications.

The shielding and spectroscopic properties of Pr+3 and Pr3+/Ho3+-codoped tellurite glass were investigated. The intensity parameters (Ω2 = 3.24-, Ω4 = 1.64-, Ω6 = 1.10 × 10-20 cm2) as well as the radiative lifetimes of 3F4 + 5S2 and 5I6 excited states of Ho3+ ions were equal to 301 μs and 3.0 μs, respectively. The former value appears to be much higher than that obtained from the lifetime measurement, indicating the presence of various energy transfer processes. The NIR spectrum of Pr3+/Ho3+-co-doped tellurite glass is dominated by strong Ho3+: 5I6 emission at around 1200 nm, being the result of the energy transfer from Pr3+ to Ho3+ ions. The shielding effectiveness of the prepared glasses showed good performance against high-energy photons. These findings suggest that the prepared glasses could be used in laser technology such as photodynamic therapy (PDT) treatment procedures and as shielding for radiation protection.

Multicolor green to orange-red emission of Tb3+ and Eu3+-codoped tellurite glasses: Eu3+ concentration and Tb3+ → Eu3+ energy transfer

Multicolor green to orange-red emission of Tb3+ and Eu3+-codoped tellurite glasses: Eu3+ concentration and Tb3+ → Eu3+ energy transfer

Ce3+ induced broadband enhancement around 2 μm in Tm3+/Ho3+ co-doped tellurite glass

Tellurite glasses doped with Tm3+, Ho3+ and Ce3+ ions were prepared via melt-quenching to realise broadband and fluorescence enhancement in near-infrared (NIR) band. Under the pumping of a commercial 808 nm laser diode (LD), the emission bands at 2.0 μm, 1.85 μm, 1.47 μm, and 705 nm were observed in the Tm3+/Ho3+ co-doping glass samples, which originated from the transitions of Ho3+:5I7→5I8 and Tm3+:3F4→3H6, 3H4→3F4, 3F2,3 → 3H6, respectively. The existence of 2.0 μm band fluorescence is due to the energy transfer from the Tm3+:3F4 level to the Ho3+:5I7 level. This band overlaps with the 1.85 μm band which forms a broadband fluorescence spectrum in the range of 1600–2200 nm. In glass samples co-doped with Tm3+/Ho3+ with 0.085 mol% Ho2O3 and 1 mol% Tm2O3, the full width at half maximum (FWHM) of this broadband spectrum (1600–2200 nm) was as high as ∼370 nm. After introducing 0.6 mol% CeO2, the emission intensity of broadband fluorescence increased by ∼50%, which was caused by the cross-relaxations between Ce3+ and Tm3+ ions. The lifetime of fluorescence decay was determined to prove the interactions among the doped rare-earth ions, the radiative parameters such as transition probability, branching ratio and radiative lifetime were calculated from the absorption spectra based on the Judd-Ofelt theory to better understand the observed luminescence phenomena. In addition, X-ray diffraction (XRD) confirmed the amorphous state structure of the synthesised glass samples, while Raman spectrum revealed the different vibrational structural units forming the glass network.

Broadband near-infrared luminescence property in Nd3+/Tm3+ co-doped tellurite glass

The near-infrared (NIR) band luminescent characteristics of tellurite glasses doped with Nd3+ and Tm3+ ions synthesized by melt-quenching conventional technology were explored. Differential scanning calorimetry (DSC) curves, Raman spectra, X-ray diffraction (XRD) patterns, absorption spectra, fluorescence spectra and fluorescence decay curves were measured. The XRD patterns demonstrated the amorphous state structural nature of the prepared glasses, the various structural units such as TeO4, TeO3+1, TeO3, BiO6, ZnO4, WO6 and WO4 were determined by Raman spectra, and DSC curves revealed the excellent thermal stability of glass host with ΔT of 150 °C. Based on the Judd-Ofelt theory, the transition probabilities and fluorescence branching ratios of the Nd3+:4F3/2→4I13/2 and Tm3+:3H4→3F4 transitions corresponding to 1.33 µm and 1.47 µm band emissions were (570.56 s−1, 10.94 %) and (320.75 s−1, 8.17 %), respectively. Under excitation at 808 nm laser diode (LD), the spectral overlap of these two bands produced a relatively flat and broadband fluorescence spectra located primarily at S + E band region with the full width at half maximum (FWHM) of 201 nm, which could provide an effective supplement to the present C + L-band of Er3+. The broadband luminescence mechanism of Nd3+ and Tm3+ ions and the interactions between them were discussed.

Enhanced 3.1µm mid-infrared emission from Er3+/Yb3+ co-doped tellurite glass pumped by 980nm laser diode

Yb3+ ions co-doping was attempted for the first time for sensitizing Er3+ ions and increasing the 3.1 µm fluorescence, originating from the transition from Er3+: 4S3/2 → 4F9/2. Under a 980 nm LD excitation, strong 3.1 µm fluorescence in the mid-infrared (MIR) region and the related energy level change process were investigated. An enhanced 3.1 µm emission was attained from the Er3+/Yb3+ co-doped tellurite glass with the increment in Yb2O3 content, which demonstrated that the Yb3+ ions may act as the sensitizer to the Er3+ ions, thereby providing an effective energy transport channel from the 2F5/2 state of Yb3+ ions to the 4S3/2 state of Er3+ions. Moreover, the measured emission band full width at half maximum reaches about 164 nm along with the maximum emission cross-section (2.88 × 10−21 cm2). The outcome of our work suggests that upon co-doping with Er3+/Yb3+, the tellurite glass may function as a prospective material for fabricating the matrix of 3.1 µm MIR lasers.