Host Glass Research Articles

Peak stimulated emission cross sections and quantum efficiencies of Sm3+ and Sm3+-Eu3+ co-doped bismuth boro-tellurite glasses

The effect of host glass composition and co-doping with Eu3+ on the optical properties of Sm3+ has been investigated in bismuth boro-tellurite glasses. The intensity parameters Ωt (t = 2,4,6), radiative transition probability (Arad) and radiative lifetimes (τrad) are obtained from optical absorption studies. Excitation spectra show that there exists energy transfer from Sm3+ to Eu3+ and vice versa. From fluorescence studies, fluorescence decay time (τexp), radiative quantum efficiencies (η), branching ratios (β) and peak stimulated emission cross section (σp) are obtained. The highest η of Sm3+ doped bismuth boro-tellurite glasses is found to be 60% and for Sm3+-Eu3+ co-doped glasses, it is 74%. Changing the host glass composition and co-doping with Eu3+ ions, the η of the glasses can be improved. The σp of Sm3+-Eu3+ doped glasses is found to be larger than that of singly doped Sm3+ glasses. Our results indicate that modifying the host glass composition and co-doping with Eu3+ can improve the emission characteristics of Sm3+ ions. Bismuth boro-tellurite glasses with enhanced values for η and σp are suitable for photonic devices and photovoltaic applications.

Synergistic effects of Nd3+ and Ag nanoparticles doping on spectroscopic attributes of phosphate glass

Abstract Efficient, inexpensive and eye−safe new host glass as up−conversion (UC) emission solid−state laser media became demanding. Nanoparticles (NPs) of various noble metals have been inserted into the phosphate−based amorphous host matrix to enhance the rare-earth ions (REIs) stimulated emission cross−section. Furthermore, only a few reports exist on the combined influences of neodymium ions (Nd3+) and pure silver (Ag) NPs on the structural and optical response of magnesium zinc sulfophosphate (MZSP) glasses. In this view, a series of MZSP glasses were doped by Nd3+ ions and pure Ag NPs (at different concentrations) to improve their structural and optical properties. Such melt−quench synthesized glasses were characterized at room temperature using diverse analytical measurement tools. The XRD pattern of as−quenched samples approved their amorphous nature. The FTIR and Raman spectra of glasses revealed the presence of characteristic bonding vibrations of different functional groups. The TEM images showed the existence of spherical Ag NPs (mean size of 8.34 nm) in the host glass matrix. The surface plasmon resonance (SPR) band of Ag NPs was detected around 451 nm. The UV–Vis–NIR absorption and PL emission spectra of glasses were utilized to evaluate the Judd−Ofelt (JO) intensity parameters ( Ω 2 , Ω 4 and Ω 6 ) and radiative properties. The observed fluctuation in the Ω 2 values with the increase in Ag NPs contents was attributed to the dynamic change of ligands symmetry around Nd3+ inside the glass network. Variations in the Ω 4 and Ω 6 values with the increase in Ag NPs contents indicated a considerable reduction in the glass rigidity. The PL spectra of glasses exhibited a prominent band around 576–584 nm corresponding to the 2G7/2 +4G5/2 → 4I9/2 transition in Nd3+. Glass prepared with 0.5 mol% of Ag NPs disclosed the highest PL enhancement (≈19 times) and largest emission cross−section (≈4.35 × 10−24 cm2) which was ascribed to the synergism between Ag NPs SPR mediated strong local field effect (LFE) and the subsequent energy transfer to Nd3+ appeared in the proximity of NPs. It was concluded that the proposed glass composition can lead to the development of UC solid−state laser compared to many other reported glass system.

Improvement in 1.53-μm-band fluorescence of Er3+/Yb3+-codoped borate glasses based on infrared energy transfer

Er3+/Yb3+-codoped borate glass consisting of B2O3–WO3–ZnO–Y2O3 was synthesized as a potential gain medium for an Er3+-doped fiber amplifier (EDFA). X-ray diffraction (XRD) patterns and Raman spectra were characterized to investigate the structural behavior of the glass host, and absorption spectra were recorded to investigate the spectroscopic properties of the Er3+/Yb3+-codoped borate glasses according to the Judd–Ofelt theory. The 1.53-μm-band emission spectra of Er3+ under 980-nm excitation were measured to verify the process of energy transfer (ET) from Yb3+ to Er3+, and the decay lifetimes of Yb3+:1020-nm emission were determined to evaluate the ET efficiency (ETE) between Yb3+ and Er3+. The results indicate that a broad 1.53-μm-band emission occurs for Er3+, with a full width at half maximum (FWHM) of approximately 82 nm. Moreover, the emission intensity increases by approximately 66.7% in Er3+/Yb3+-codoped borate glass containing 10.0 mol% Yb3+, which is ascribed to the efficiency ETE of Yb3+:2F5/2 + 4I15/2 → Yb3+:2F7/2 + Er3+:4I11/2. Compared with the previously reported glass systems, the prepared borate glasses have the typical features, including high gain and broad emission at 1.53-μm, which provide a new route to improve the signal gain in the C-band and further develop the short-length optical amplifiers.

Concentration-dependent reddish-orange photoluminescence studies of Sm3+ ions in borosilicate glasses

Abstract This paper elucidates the concentration-dependent photoluminescence properties of samarium ions in Lithium bismuth alumino borosilicate (LiBiAlBSi) glasses using XRD, FT-IR, absorption, excitation, emission & decay to quantify the luminescence properties of the titled glasses. XRD and FT-IR spectral data ascertain the non-crystalline nature and vibrational energies in host glass respectively. The intense excitation band observed at 400 nm in near UV region (under λem = 600 nm) is employed to read the emission spectra. Under 400 nm intense excitation wavelength, the titled glasses show intense visible reddish-orange emission at 600 nm. From the emission spectra, it is observed that 0.5 mol% of Sm3+ ions concentration in LiBiAlBSi glass is optimum for reddish-orange emission. The CIE coordinates estimated for LiBiAlBSi glasses are in good proximity with the reddish-orange emission coordinates specified by Nichia Corporation. Branching ratios, emission cross-sections, quantum efficiency, and CIE coordinates estimated finally reveals the aptness of the LiBiAlBSi glasses for reddish-orange optoelectronic device applications.

Influence of ZrO2 Addition on Structural and Biological Activity of Phosphate Glasses for Bone Regeneration.

Zirconium doped calcium phosphate-based bioglasses are the most prominent bioactive materials for bone and dental repair and regeneration implants. In the present study, a 8ZnO–22Na2O–(24 − x)CaO–46P2O5–xZrO2 (0.1 ≤ x ≤ 0.7, all are in mol%) bioglass system was synthesized by the conventional melt-quenching process at 1100 °C. The glass-forming ability and thermal stability of the glasses were determined by measuring the glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm), using differential thermal analysis (DTA). The biological activity of the prepared samples was identified by analyzing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy dispersive spectra (SEM-EDS), before and after immersion in simulated body fluid (SBF) for various intervals of 0, 1 and 5 days, along with the magnitude of pH and the degradation of glasses also evaluated. The obtained results revealed that the glass-forming ability and thermal stability of glasses increased with the increase in zirconia mol%. The XRD, FTIR, and SEM-EDS data confirmed a thin hydroxyapatite (HAp) layer over the sample surface after incubation in SBF for 1 and 5 days. Furthermore, the development of layer found to be increased with the increase of incubation time. The degradation of the glasses in SBF increased with incubation time and decreased gradually with the increase content of ZrO2 mol% in the host glass matrix. A sudden rise in initial pH values of residual SBF for 1 day owing to ion leaching and increase of Ca2+ and PO43− ions and then decreased. These findings confirmed the suitability of choosing material for bone-related applications.

Intense red emission via energy transfer from (Ce3+/Eu3+):P2O5+NaF+CaF2+AlF3 glasses for warm light sources

Europium (Eu3+)-doped fluorophosphate (PNCA:P2O5+NaF + CaF2+AlF3) glasses with the addition of cerium (Ce3+) ions were fabricated by the melt-quenching technique to know their ability for the bright red (615 nm) luminescence. The emission (PL) and excitation (PLE) spectra, decay curve measurements as well as energy transfer (ET) process of Ce3+→ Eu3+ were studied in detail. An excitation spectrum related to the 7F0→ 5D2 level of Eu3+ is used to estimate the phonon energy (1121 cm−1) of the title glass host. Under ultraviolet (UV) irradiation of 299 nm, the PL spectra of (Ce3+/Eu3+):PNCA glasses show intense red emission at 615 nm whereas the lifetime decrease with respect to increase of Eu3+ that could support the observed efficient ET from Ce3+ to Eu3+. The ET:Ce3+ →Eu3+ via quadrupole-quadrupole process was confirmed by Reisfeld's approximation and Dexter's ET formula. The ET efficiency (ηET) and critical distance (Rc) were also calculated. Interestingly, the (Ce3+/Eu3+):PNCA glasses showed intense red light emission with low correlated color temperatures and the corresponding color purity reached as great as 99%, indicating its potentiality as a red component for warm light sources.

Spectroscopic properties of neodymium doped magnesium zinc sulfophosphate glass: Synergistic effects of titanium and silver nanoparticles embedment

Abstract Synergistic effects of two distinct metal/semiconductor nanoparticles (NPs) upon incorporation into different materials medium have shown to open up a new frontier in material research. In this view, two series of neodymium ions (Nd3+) doped magnesium zinc−sulfo phosphate glass glasses composition 58.5P2O5–20MgO–20ZnSO4–1.5Nd2O3–0.5AgNPs−yTi NPs (where y = 0.1, 0.2, 0.3 and 0.4 mol% in excess) and 58.5P2O5–20MgO–20ZnSO4–1.5Nd2O3–0.4TiNPs−xAg NPs (where x = 0.1, 0.2, 0.3, 0.4 and 0.5 mol% in excess) were prepared via melt−quenching method. The as-synthesized samples were characterized to determine the combined effects of silver (Ag)/titanium (Ti) NPs inclusion on their spectroscopic properties. XRD analyses of as-quenched samples confirmed their amorphous nature. The FTIR and the Raman spectra revealed the presence of characteristic vibration bonds inside the studied glass network. The HRTEM images verified the nucleation of both Ag and Ti3O5 NPs inside the host matrix. The occurred twelve absorption bands centred at 352, 430, 458, 473, 512, 526, 582, 626, 682, 745, 802 and 875 nm were assigned to the respective transitions from the ground state (4I9/2) to the excited states of 2D1/2+4D3/2+4D5/2, 2P1/2, 4G11/2, 2D3/2+2P3/2+2G9/2, 4G9/2+2K13/2, 4G7/2, 4G5/2+2G7/2, 2H11/2, 4F9/2, 4F7/2+4S3/2, 4F5/2+2H9/2 and 4F3/2 in Nd3+. The probed surface plasmon resonance (SPR) band of Ag NPs (at 442 nm) and Ti3O5 NPs (at 585 and 730 nm) indicated their successful embedment within the glass matrix. Meanwhile, the SPR bands of both NPs disclosed a slight red−shift when embedded together inside the glass compared to their individual incorporation which was ascribed to the near field effect mediated alteration in natural frequency of the oscillator. The observed prominent yellow band around 585 nm in the photoluminescence (PL) spectra of glasses was approved to the transition of 2G7/2+4G5/2 → 4I9/2. The NIR PL spectra depicts bands around 874 nm, 1050 nm and 1322 nm, corresponding to 4F3/2 → 4I9/2, 4F3/2 → 4I11/2 and 4F3/2 → 4I13/2 transitions respectively. The evidenced PL intensity quenching in the glass prepared bands around with both Ag and Ti3O5 NPs was attributed to the effect of metallic NPs mediated local heating. Judd-Ofelt (JO) theory was used to evaluate the spectroscopic properties of the glass and make contact with experimental findings. Sample embedded with 0.4 mol% of Ti NPs together with 0.3 mol% of Ag NPs showed highest stimulated emission cross−section (4.78 × 10−24 cm2) for transition 2G7/2+4G5/2 → 4I9/2. It was established that the synergistic effects of two types of metal NPs embedded inside the Nd3+ doped proposed host glass may be useful to achieve customized spectroscopic properties required for solid state laser and photonic application.

Ruthenium solubility and its impact on the crystallization behavior and electrical conductivity of MoO3-containing borosilicate-based model high-level nuclear waste glasses

The present study focuses on investigating the solubility of RuO2 in a borosilicate-based model high-level waste glass and understanding its impact on the crystallization behavior and electrical conductivity of the resulting vitrified waste forms. The solubility limit of RuO2 in the investigated glass composition has been determined to be 460 ppm by weight. The higher concentration of RuO2 results in sub-micron sized Ru-rich inclusions in the glassy matrix, which eventually agglomerate to form needle-like and polyhedral RuO2 crystals. It is observed that RuO2 selectively promotes the crystallization of the rare-earth apatite phase over the powellite phase. The as-synthesized RuO2-containing glasses exhibit semiconducting behavior with a similar level of electrical conductivity below the glass transition. The percolation of non-uniformly distributed RuO2 inclusions may result in a formation of short-range low-resistive conduction pathways in the host glass matrix leading to an apparent metallic-like behavior of selected thin samples with the highest ruthenium content.

Modified structure and spectroscopic characteristics of Sm3+/Dy3+ co-activated barium-sulfur-telluro-borate glass host: Role of plasmonic gold nanoparticles inclusion

This paper reports the pure gold nanoparticles’ (AuNPs) localized surface plasmon field mediated structural and spectroscopic modification of the Sm3+/Dy3+ co-activated barium-sulfur-telluro-borate glasses. These glass samples were synthesized via melt-quenching technique and characterized to determine the role of pure gold nanopowder embedment at different contents on their structures and optical traits. The TEM image analysis showed that the non-spherical shaped AuNPs with an average diameter of 29 nm were successfully embedded into the host glass matrix. The symmetry of the Sm3+/Dy3+ environment was increased with the increase of AuNPs contents, indicating a decreasing trend of the bonding parameter values from −0.08 to −1.25, Judd-Ofelt intensity parameter (Ω2) from 4.39×10-20 to 1.15×10-20 cm2 and crystal field strength from 9.28 to 5.99. Furthermore, the trend of the evaluated radiative parameters revealed their sensitivity to the alterations in the glass structure. The AuNPs localized surface plasmon field stimulation significantly affected the structural and spectroscopic qualities of the glasses, leading to a shift in the chromaticity co-ordinates from the white to yellowish-orange zone in the CIE 1931 color space. Overall, the proposed glass system was established to be a potential yellowish-orange light-emitting laser host matrix.

Influence of (Er3+, La3+, Ce4+) additions on physical and optical properties of 50CaO–50P2O5 glasses

Calcium phosphate glass samples with the addition of 5 mol% of three different rare earth oxides (Erbium, Lanthanum and Cerium oxides) were made by melt quenching process. Effect of rare earth ions addition on structural, physical and optical properties has been investigated using density measurement, XRD diffraction, Fourier transformed infrared (FTIR) spectroscopy, ultra violet visible spectroscopy and Abbe Refractometer. The random short range order of synthesized glass samples was analyzed by XRD diffraction. The absorption spectra have been recorded and optical band gap energy was determined by using Tauc plotting. The band gap energy showed a decrease when 5 mol% of rare earth (Er2O3, La2O3, and CeO2) oxides were added to the host glass. Fourier transformed infrared (FTIR) spectrometer was applied to study the structural changes of the synthesized glasses. The density and refractive index of synthesized glasses was measured and related parameters were calculated. These values are compared with the un-doped metaphosphate glass. Based on measured density, the concentrations of added rare-earth ion is calculated. With an increase in ion concentration, the internuclear distance decreased leading to an increase in field strength.

Compositional dependence of red photoluminescence of Eu3+ ions in lead and bismuth containing borate glasses

Herein, heavy metal borate glasses activated with different concertation of Eu2O3 were prepared via the melt quench method. The Eu3+ concentration effect on photoluminescence (PL) properties of prepared glasses was investigated and discussed in detail to understand their utility in solid-state lighting and other photonic applications. The present work explains the suitability of two heavy metal oxides such as PbO and Bi2O3 for Eu2O3 doping to develop the glassy materials for photonic applications. The PL intensity was increased with an increase in Eu3+ content in PbO framed borate glasses while in Bi2O3 containing borate glasses the PL intensity was decreased at higher concentration due to concentration quenching. The Judd–Ofelt parameters and the radiative properties suggest the heavy metal borate glass hosts activated with 1 mol % of Eu3+ were potential materials for red light-emitting devices under blue light excitations. The Lifetime values of the PbO framed glasses were greater compared to Bi2O3 framed borate glasses which suggest the borate glass host containing high PbO content is more precisely suitable than Bi2O3 containing borate glass for solid-state lighting applications under blue light excitation.

Luminescent ion-doped transparent glass ceramics for mid-infrared light sources [invited

Glass ceramics (GCs), which consist essentially of a homogeneous solid state dispersion of nanocrystals (NCs) embedded in a chemically inert and mechanically robust glass matrix, appear to be an extremely promising class of solid state materials that can be easily tailored into arbitrary shapes, including a new generation of optical fibers, for efficient incoherent and coherent sources of mid-infrared (MIR) light emission. This unique capability not only stems from the fact that one can tailor the underlying glass matrix for optimal macroscopic physical properties and ultrahigh transparency at the wavelengths of interest (resulting in appropriate "transparent glass ceramics" or TGCs), but also stems from the fact that one can embed these matrices with size and structure-tailored NCs, which in turn can be doped with relatively high concentrations of MIR emitting rare-earth or transition metal ions. This potential is tantamount to the localization of these highly efficient MIR ionic emitters into carefully selected and highly favorable "process-engineered" custom crystalline host "nanocages," while insulating the ionic emitters from the emission-quenching glass host matrix, the latter being chosen largely because of its highly favorable macroscopic bulk properties, including its ductility and formability into near-arbitrary shapes (at appropriate temperatures). Such MIR TGCs appear to be very promising for numerous photonics applications, including compact and relatively efficient waveguide sensors, broadband incoherent MIR light sources, superluminescent light sources, advanced fiber-optic devices, and broadly wavelength-tunable and ultrashort pulse mode-locked fiber and bulk solid-state lasers. In this paper, we review past achievements in this field, starting with an overview of TGCs, followed by discussions of currently preferred methods of fabrication, characterization, and optimization of suitably doped oxyfluoride, tellurite, and chalcogenide TGCs and of our projections of anticipated future developments in this field at both the materials and device levels.

Energy transfer from Mn2+ to Nd3+ ions embedded in a nanostructured glass system with Zn1−xMnxTe nanocrystals

In this work, we study energy transfer (ET) processes between Mn2+ and Nd3+ ions in Nd2O3-doped P2O5–ZnO–Al2O3–BaO–PbO glass system, nanostructured with Zn1−xMnxTe diluted magnetic semiconductor nanocrystals (NCs), aiming nanotechnology applications. Transmission electronic microscopy (TEM), X-ray diffraction (XRD), optical absorption (OA), photoluminescence (PL), and lifetime measurements were performed for a complete characterization of the investigated materials. The TEM and XRD data confirm the formation of Zn1−xMnxTe NCs in the host glass system. The overlap between the Mn2+ ion emission band and the Nd3+ ion absorption bands suggests that an efficient resonant type energy transfer from Mn2+ to Nd3+ ions is expected. PL spectra show that the characteristic emission relative intensities of Nd3+ ions increase systematically with increasing Mn concentration. Indeed, the 4T1(4G) state lifetime of Mn2+ ions gradually decreases with rising Mn concentration. This result confirm the evidence on ET from Mn2+ ions to Nd3+ ions. In addition, the increase in the 4F3/2 state lifetime is an evidence of persistent luminescence due to the presence of Mn2+ ions.

Reddish-orange emission and Judd-Ofelt investigation of Sm3+ ions doped in zince-bismuth-phospho-tellurite glasses for solid lighting application

In this paper, physical, structural and optical properties of zinc bismuth phospho tellurite glass doped with various concentration of Sm3+ ions (x = 0.01, 0.1, 0.3, 0.5 and 1 mol%) were prepared by melt quenching technique. With keen interest in luminescence properties of samarium, spectroscopic properties are investigated using optical absorption spectra, excitation spectra, emission spectra and decay profiles. Applying Judd-Ofelt theoretical approach an effort is made to understand the asymmetry of samarium in phosphate host glass matrix. Using this theory three important parameters such as Ω2, Ω4, Ω6 are determined to calculate emission properties for certain Sm3+ transitions. Luminescence parameters such as stimulated emission cross section (σp) and branching ratios (βexp) have been studied through photoluminescence spectra. The PL spectra for all glasses show four emission bands centered between 561, 601, 646 and 708 owing to the 4G5/2 → 6H5/2 (561), 6H7/2 (601), 6H9/2(646) and 6H11/2(708) transitions of Sm3+ doped PZBTS glass system. Decay time data reveals that single exponential behavior of Sm3+ ions up to 0.5mol%, while non-exponential decay profile for 1 mol% Sm3+ content. CIE1931 chromaticity diagram for the PZBTS glasses were evaluated. CCT values were obtained and shows around 2510 K–2560 K for the prepared glasses. From the results we say that these materials prove to be very good materials for reddish orange lighting applications.

Structural and Optical Study of CoO Doping in Borophosphate Host Glass and Effect of Gamma Irradiation

A series of borophosphate based glasses were prepared with a main composition (50P2O5–30B2O3–10CaO–10Na2O ) wt%. The effect of addition wt% (of cobalt oxide (0.2, 0.5, 0.7) g in different forms is the main purpose of this study. Structural and optical properties of the prepared glasses were obtained using both FITR and UV–Visible techniques. The optical band gap was evaluated from the optical absorption spectral data. XRD was investigated to indicate the formed phases of prepared systems. Density measurements also were done using Archimedes method. The effect of successive gamma irradiation by various doses (10, 30, 50 KGy not) on the different properties of the prepared glasses were measured.

Size-controlled emission of long-time durable CsPbBr3 perovskite quantum dots embedded tellurite glass nanocomposites

Among various semiconductor quantum dot materials, all-inorganic CsPbBr3 perovskite quantum dots (PQDs) are at the center of ongoing research with their excellent optical properties. However, poor durability of CsPbBr3 PQDs under ambient conditions, e.g. oxygen, heat, moisture, light-exposure, results in keeping them away from long-term practical applications. One of the most promising approaches to improve their durability is the preservation of CsPbBr3 PQDs in oxide glass hosts. Therefore, in this study, CsPbBr3 PQDs are successfully embedded inside a tellurite-based glass via melt-quenching and subsequent heat-treatment. Pure cubic structure of CsPbBr3 PQDs is confirmed by X-ray diffraction analysis. Radii of PQDs are tuned in the range of 2.36–4.89 nm and emission color modulation between 469 and 520 nm with narrow full width at half maximum values of 16–23 nm is realized by band gap tailoring from 3.03 eV to 2.41 eV through rigorous heat-treatment procedures. CsPbBr3 PQDs exhibit superior thermal and chemical durability and impressively stable photoluminescence properties due to strong protection of tellurite glass host. Consequently, excellent long-term durability along with highly pure and tunable emission colors of CsPbBr3 PQDs embedded tellurite glass nanocomposites may lead the way of these outstanding materials through practical photonic and opto-electronic applications.

Orange color emitting Sm3+ ions doped borosilicate glasses for optoelectronic device applications

An intense orange color emitting Sm3+ activated Li2O–PbO–ZnO–Al2O3–B2O3–SiO2 (LPZABS) glasses were propitiously fabricated by using sudden quenching method to study the luminescent potentiality using spectroscopic techniques such as XRD, FT-IR, optical absorption, photoluminescence (PL) and PL decay. XRD and FT-IR reveals the glassy nature and various functional groups present in LPZABS host glass respectively. Judd-Ofelt parameters derived from absorption spectra are used to estimate various radiative parameters for the excited states of Sm3+ ions in LPZABS glasses. Under 400 nm excitation, the luminescence spectra in the as prepared glasses exhibit three emission bands that corresponds to 4G5/2 → 6H5/2 (562 nm), 4G5/2 → 6H7/2 (598 nm) and 4G5/2 → 6H9/2 (645 nm) transitions of Sm3+ ions. Among these three, 4G5/2 → 6H9/2 transition observed in orange region (598 nm) is relatively more intense and prominent. The PL decay curves recorded for 4G5/2 fluorescent level reveal exponential behavior and single exponential fitting is applied to evaluate the experimental lifetimes (τexp). The τexp values are found to be decreasing with Sm3+ ion content due to cross-relaxation energy transfer process. The results reveal that the as prepared glasses can be effectively used in fabricating intense visible orange color emitting optoelectronic devices.

First demonstration of ~ 5 µm laser action in terbium-doped selenide glass

4.9–5.5 µm laser oscillations were observed in high-purity bulk terbium-doped Ge36Ga5Se59 glass pumped by pulsed 2.93 µm Er:YAG laser. This is the first evidence of laser action corresponding to 7F5–7F6 transition of Tb3+ ions and of mid-infrared lasing in chalcogenide glass host.

Judd−Ofelt calculations for spectroscopic characteristics of Dy3+-activated strontium magnesium borate glass

Some new type of strontium magnesium borate glass system doped with Dy3+ (various contents 0.1, 0.3, 0.5, 0.7 and 1.0 mol%) were produced using the conventional melt-quenching. Obtained glasses were thermally stable, highly transparent, and moisture resistant. As-prepared samples were characterized to determine their spectroscopic traits. The Judd-Ofelt (J-O) intensity Ωλ (λ = 2, 4, 6) and radiative parameters were calculated to validate the experimental results on the optical characteristics. The XRD pattern of the as-quenched samples verified their glassy nature, FESEM images showed uniform textures and EDX analyses detected the presence of appropriate constituents in the host matrix. Glass containing 0.7 mol% of Dy3+ revealed the optimum optical traits where the luminescence emission intensity was attenuated beyond this content. The optical gain for two intense emission transitions (4F9/2→6H15/2 and 4F9/2→6H13/2) was evaluated. The values of Ωλ (λ = 2, 4, 6) determined the ionic nature of the bonding and symmetry environment of the Dy―ligand matrix based on the viscosity and rigidity of the host glass. The 6H15/2→6F11/2 transition was hypersensitive. The ratio of the yellow to blue (Y/B) emission intensity less than unity indicated the lower degree of covalence between Dy3+ and O2− ions thereby makes these glasses effective for the near UV―LEDs. The higher values of the branching ratio (≥ 50 %) and stimulated emission cross-section enabled the proposed glass composition potential for the optical amplifiers and fibres fabrication. The resonant energy transfer and cross-relaxation processes in the Dy3+ were attributed to be responsible for the improved optical features.

White light emission from Dy3+-doped ZnO + Bi2O3 + BaF2 + B2O3 + TeO2 glasses: Structural and spectroscopic properties

The ZnO+Bi2O3+BaF2+B2O3+TeO2 (ZnBiBaBFTe) host glass was prepared by melt quenching technique with the aim of achieving white light emission from Dy3+ ions. Their structural and spectroscopic properties were systemically investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Visible absorption, emission spectra and decay times. Judd-Ofelt (JO) parameters (Ωλ) evaluated from absorption spectrum were utilized to calculate the radiative parameters for 4F9/2 level of Dy3+ ions. The optical band gap energy of as-prepared glasses were calculated for the indirect, (αhυ)1/2 and direct, (αhυ)2 allowed transitions. The emission spectra of Dy3+:ZnBiBaBFTe glasses showed two intense peaks at 575nm (4F9/2→6H13/2) and 481nm (4F9/26H15/2) upon 386nm excitation. The highest emission intensity was observed at 1.0mol% of Dy3+ for 4F9/2→6H13/2 transition and the results are used in conjunction with lifetime measurements to derive spectroscopic parameters for the stimulated emission cross-section (25.2×10-22cm2), gain bandwidth (5.86×10-28cm3), and favourable quantum efficiency (74.2%). Moreover, white light can be realized with a CIE coordinates by adjusting the concentration of Dy3+ ions in ZnBiBaBFTe host glass. Efficient spectroscopic values and realizable white lighting in Dy3+-doped ZnBiBaBFTe glasses may have potential applications in laser illumination devices.