Ions Nd3 Research Articles

Efficient in situ synthetic routes of the polymeric composite containing clinoptilolite using ultrasonic assistance for sorption of some lanthanides

The ultrasound assistance synthesis strategy of the polymeric composite is based on free radical polymerization of polyallylamine hydrochloride (PAH) cationic polyelectrolyte, with vinyl sulfonic acid (VSA) anionic monomer with microporous crystalline alumino silicate clinoptilolite clay. The P(AH-co-VSA)/clinoptilolite polymeric composite was fully characterized by fourier transform infrared spectroscopy, energy dispersive X-ray, thermogravimetric analysis, and scanning electron microscope. FTIR demonstrated the presence of PAH and VSA, confirming the composition of the prepared composite. It was also used to map the energy-dispersive X-ray to affirm the interdependence of the clinoptilolite into the polymeric matrix. Consequently, the physicochemical characteristics of this copolymer may be adjusted using VSA and PAH suitable combinations. Batch experiments were applied and maximal sorption capacities for studied ions Nd3+, Ce3+, Y3+, Gd3+, and Eu3+ were 36.6, 50.2, 55.9, 57.2, and 57.7 mg/g, respectively. Sorption kinetics and equilibrium isotherm were conducted. Experimental isotherms of studied ions were successfully fit to pseudo-second-order model, langmuir isotherm model. The Dubinin–Radushkevich (D–R) isotherm was found to be applicable and suggesting that, the sorption occurs via a ion exchange reaction. The breakthrough data were measured in a fixed bed column, and variable process factors were examined, including bed depth, flow velocity, and initial metal ion concentration. The experimental work was then focused, for continuous investigations, on Ce3+, Eu3+, and Y3+ to represent light, intermediate, and heavy lanthanides respectively. The overall bed capacity and total metal ion adsorption increased when the flow rate increased. They reduced with rising initial metal ion concentration and bed depth, and reached 22.8, 31.4, and 28.5 mg/g for Ce3+, Eu3+, and Y3+ metal ions, respectively.

Multichannel sensor array based on carbon dots and metal ions system for physiological phosphates sensing

The detection of physiological phosphates is crucial for elucidating metabolic processes and related diagnoses of diseases. Herein, a carbon dots (CDs) modulated multichannel fluorescent sensor array was proposed for detecting and distinguishing physiological phosphates. In this sensor, three metal ions (Nd3+, Ag+, and Fe3+) with significantly different binding forces with phosphate ions were selected to trigger fluorescence quenching of three CDs (BCDs, GCDs, and RCDs). Upon adding physiological phosphates, the fluorescence intensity of CDs changed. Depending on the discrepancy in the content of phosphate units in different physiological phosphates, the sensor array realized the detection and differentiation of five physiological phosphates related to adenosine triphosphate (ATP) hydrolysis, and has good anti-interference ability, which can realize the differentiation of physiological phosphates in complex serum samples.

Role of Nd (III) ions on B2O3–TeO2-GeO2-MgO glass composition for optical and ionizing protection application

In this investigation, we reported three glass samples of Nd (III) ions doped boro-tellurite-germanite glasses. The chemical composition of (35-x) B2O3–20TeO2-10GeO2-35MgO-xNd2O3 where x = 2.5, 5, and 7.5, all in mol%, was used to synthesize an optical glass. XRD, FTIR, and optical absorption were utilized to evaluate the structural and optical properties of Nd2.5, Nd5.0, and Nd7.5. X-ray diffraction was measured in the spectra range of 10–80°. Additionally, spectra of FT-IR in the wavenumber range of 400–4000 cm−1 were reported to investigate all structural groups. Several absorption peaks related to the transitions from ground level 4I9/2 to the other excited state were investigated. Various mechanical, optical, and physical properties were calculated theoretically and analyzed to determine the role of the rare earth ions (Nd3+). The optical electronegativity (χ) and optical basicity (Λ) results showed a reduction in the strength of the bond and formed an ionic bond in the glass structure due to adding Nd2O3. These results align with the reduction in the elastic modulus results by adding Nd2O3 instead of B2O3. Radiation shielding parameters like HVL, TVL, MFP, and Zeff were thoroughly reported for all Nd2.5, Nd5.0, and Nd7.5, which showed slight improvement when Nd2O3 was added instead of B2O3.

Study on the Luminescence Performance and Anti-Counterfeiting Application of Eu2+, Nd3+ Co-Doped SrAl2O4 Phosphor.

This manuscript describes the synthesis of green long afterglow nanophosphors SrAl2O4:Eu2+, Nd3+ using the combustion process. The study encompassed the photoluminescence behavior, elemental composition, chemical valence, morphology, and phase purity of SrAl2O4:Eu2+, Nd3+ nanoparticles. The results demonstrate that after introducing Eu2+ into the matrix lattice, it exhibits an emission band centered at 508 nm when excited by 365 nm ultraviolet light, which is induced by the 4f65d1→4f7 transition of Eu2+ ions. The optimal doping concentrations of Eu2+ and Nd3+ were determined to be 2% and 1%, respectively. Based on X-ray diffraction (XRD) analysis, we have found that the physical phase was not altered by the doping of Eu2+ and Nd3+. Then, we analyzed and compared the quantum yield, fluorescence lifetime, and afterglow decay time of the samples; the co-doped ion Nd3+ itself does not emit light, but it can serve as an electron trap center to collect a portion of the electrons produced by the excitation of Eu2+, which gradually returns to the ground state after the excitation stops, generating an afterglow luminescence of about 15 s. The quantum yields of SrAl2O4:Eu2+ and SrAl2O4:Eu2+, Nd3+ phosphors were 41.59% and 10.10% and the fluorescence lifetimes were 404 ns and 76 ns, respectively. In addition, the Eg value of 4.98 eV was determined based on the diffuse reflectance spectra of the material, which closely matches the calculated bandgap value of SrAl2O4. The material can be combined with polyacrylic acid to create optical anti-counterfeiting ink, and the butterfly and ladybug patterns were effectively printed through screen printing; this demonstrates the potential use of phosphor in the realm of anti-counterfeiting printing.

Rare Earth Element Binding and Recovery by a Beta Roll-Forming RTX Domain.

The Block V of the RTX domain of the adenylate cyclase protein from Bordetella pertussis is disordered, and upon binding eight calcium ions, it folds into a beta roll domain with a C-terminal capping group. Due to their similar ionic radii and coordination geometries, trivalent lanthanide ions have been used to probe and identify calcium-binding sites in many proteins. Here, we report using a FRET-based assay that the RTX domain can bind rare earth elements (REEs) with higher affinities than calcium. The apparent disassociation constants for lanthanide ions ranged from 20 to 75 μM, which are an order of magnitude higher than the affinity for calcium, with a higher selectivity toward heavy REEs over light REEs. Most proteins release bound ions at mildly acidic conditions (pH 5-6), and the high affinity REE-binding lanmodulin protein can bind 3-4 REE ions at pH as low as ∼2.5. Circular dichroism (CD) spectra of the RTX domain demonstrate pH-induced folding of the beta roll domain in the absence of ions, indicating that protonation of key amino acids enables structure formation in low pH solutions. The beta roll domain coordinates up to four ions in extreme pH conditions (pH < 1), as determined by equilibrium ultrafiltration experiments. Finally, to demonstrate a potential application of the RTX domain, REE ions (Nd3+ and Dy3+) were recovered from other non-REEs (Fe2+ and Co2+) in a NdFeB magnet simulant solution (at pH 6).

Optimal Doping Concentrations of Nd3+ Ions in CYGA Laser Crystals

The kinetic process of the excited state population of Nd3+ ion in Nd: CaY0.9Gd0.1AlO4 (Nd: CYGA) crystal were studied in detail to estimate the optimal doping concentration, which maximize ~1 μm fluorescence emission from the 4F3/2 state to the 4I9/2 state of Nd3+. The analysis was accomplished by revealing the dependence of the excited state population on the doping concentration in a relatively convenient way in theory. After comparing the theoretical prediction results with the experimental findings and approximating the results obtained using the aforementioned method, the optimal relative doping concentration of Nd: CYGA was determined to be 2.1 at.%, which closely matched the 2.0 at.% obtained through experimental comparison. This verifies the effectiveness and accuracy of the proposed method. In particular, it is worth mentioning that in this method only one doping concentration of the crystal is required to obtain the optimal concentration, which may be used to guide the concentration optimization process for improving efficiency and saving resources.

Energy transfer and laser gain cross-section analysis in Nd-Yb-Gd doped CaF2 crystals

A detailed spectroscopic characterization of CaF2 co-doped with neodymium and ytterbium ions is presented. The higher Nd3+ absorption cross-section around 791 nm than Yb3+ around 980 nm enables an efficient excitation of Yb3+ ions by pumping Nd3+ with a subsequent energy transfer (ET) from Nd3+ to Yb3+ ions. By combining Nd3+ and Yb3+, along with Gd3+ buffer ions Nd3+,Yb3+,Gd3+:CaF2 crystals exhibit very large emission bands extending the usual Yb3+ emission spectrum by adding the Nd3+ emission contribution at longer wavelengths. The Nd3+ ⟶ Yb3+ energy transfer efficiency is estimated using two different approaches based on luminescence intensity measurements and lifetimes, giving consistent results. An energy transfer efficiency of 80 % is achieved in CaF2:0.5%Nd,3%Yb,2%Gd illustrating the ET strength within Nd3+-Yb3+ clusters. Finally, a detailed study of the gain cross-sections and laser emission spectra, and their dependence with Yb3+ doping concentration and population inversion is carried out, providing a detailed model of the laser spectral dynamics in such crystals. The gain cross-section is either dominated by one of the Nd3+ peaks at 1065 nm or 1048 nm or exhibits a flat profile covering the 1045–1067 nm range, in which case the laser oscillates randomly over this spectral range. The results highlight the specifics of the Nd3+ four level laser coupled by energy transfer to the Yb3+ quasi three level laser. Among others, this study shows how a large Nd3+ inversion ratio initiates the depletion of the Yb3+2F7/2 ground state through the ET. This depletion then has two effects as it saturates the energy transfer since the number of Yb3+ acceptors diminishes and it also shifts the laser wavelength towards shorter wavelength as the Yb3+ laser reabsorption is weakened.

Crystal growth and spectral properties of a mixed crystal Nd3+:LuYPO4

A new mixed orthophosphate crystal of Nd3+:LuYPO4 was grown by high temperature solution method successfully. The optical properties including polarized absorption and emission spectra as well as the fluorescence decay curve have been investigated in detail. The calculated absorption cross-sections were 18.6 × 10−20 cm2 at 803 nm with a FWHM of 6.10 nm for π-polarization and 8.96 × 10−20 cm2 at 804 nm with a FWHM of 6.07 nm for σ-polarization, respectively. The broad absorption bands wider than those of Nd:YPO4 and Nd:LuPO4 crystals confirm that the incorporation of Lu3+ ions results in a effectively inhomogeneous broadening of the spectra. Based on J-O theory, some typical parameters such as J-O intensity, fluorescence branching rate and radiation lifetime of Nd3+ ions in Nd:LuYPO4 crystal were systematically calculated. Besides, five strong emission peaks located at 1054, 1061, 1066, 1076 and 1081 nm can be observed obviously from fluorescence spectra. All the results show that Nd:LuYPO4 crystal is a promising laser material applied to 1.0 μm with multi-wavelength emission characteristics.

Energy-looping and photon-avalanche-like phenomena in NdxY1.00-xAl3(BO3)4 powders excited at 1064 nm

Recently, a photon-avalanche-like (PA-like) process based on trivalent neodymium ions (Nd3+) under an unconventional excitation at 1064 nm was demonstrated using stoichiometric NdAl3(BO3)4 particles. Although the Nd3+ can emit radiation at 1064 nm efficiently, they present very small absorption at this wavelength due to the absence of resonant ground-state transitions. However, phonon-assisted excitation (4I9/2 → 4F3/2 and/or 4I11/2 → 4F3/2) followed by cross-relaxation between one excited ion (4F3/2) with another at the ground state (4I9/2), and subsequent phonon emissions {4I15/2, 4I15/2 → 4I13/2, 4I13/2 → 4I11/2, 4I11/2}, provide two ions at the 4I11/2 state, from which can occur the resonant excited-state absorption to the 4F3/2 level. Reestablishing this sequence of events, the absorption of photons at 1064 nm can be greatly increased. Besides the emission around 880 nm (4F3/2 → 4I9/2), there are thermal excitations to upper-lying states, with subsequent emissions in the visible and near-infrared regions (480–2000 nm). Here, we investigate the role of the Nd3+ content on the PA characteristics in NdxY1.00-xAl3(BO3)4 particles with x ranging from 0.05 to 1.00. It is known that the replacement of Y3+ by Nd3+ into the YAl3(BO3)4 crystalline structure can introduce strong modifications of the lattice properties as well as in the photoluminescence characteristics, such as luminescence concentration quenching and broadening of spectral lines. Despite that, we observed, for low x (≤0.20), an energy-looping preceding the PA-like that ensues for x ≥ 0.40. It is associated to the proximity between the Nd3+ ions, fundamental to the electric dipole-electric dipole interaction responsible for the Nd3+ energy transfer {4F3/2, 4I9/2} → {4I15/2, 4I15/2}. We discuss the present results focusing on emerging technologies with development of ultra-sensitive thermal sensors.

Structural, elastic and optical properties of rare earth ions (Nd3+, Dy3+, & Nd3+/Dy3+) incorporated B2O3+K2O+ZnO+ZnF2 glasses

Herein we report the effect of rare earth ion; REI (Nd3+, Dy3+, & Nd3+/Dy3+) on the structural, optical, luminescence and elastic characteristics of B2O3+K2O+ZnO+ZnF2 glasses produced via the melt-quenching process. The structural, optical, luminescence and elastic features of the produced glass samples were comprehensively characterised using XRD, FTIR, UV–Visible, Luminescence, and decay analysis methods. The XRD study shows that even after doping or co-doping with REIs, the glass samples exhibit amorphous characteristics. It was observed that physical parameter analysis revealed the occurrence of non-bridging oxygens, while FTIR analysis revealed the predominance of borate groups for all the prepared samples. Only transition peaks discovered in the BNd, BNdDy and BDy samples were affected, according to a UV–visible absorption spectra examination, while the rest were left unchanged. Ionic and covalency nature with the host were identified, respectively, followed by the Judd-Ofelt analysis for BNd and BDy glasses. Peak emission and lifetime data were analysed for samples of BNd, BDy, and BNdDy. The CIE diagram shows that the BDy emits warm white light with an efficiency of 81%. Using the Makishima - Mackenzie model, the structural compactness (elastic properties) of the manufactured sample was thoroughly addressed.

Handheld NIR-to-NIR Platform for on-site evaluating protective neutralizing antibody against SARS-CoV-2 ancestral strain and Omicron variant after vaccination or infection

Lateral flow assays (LFAs) are promising points-of-care tests, playing a vital role in diseases screening, diagnosis and surveillance. However, development of portable, cheap, and smart LFAs platform for sensitive and accurate quantification of disease biomarkers in complex media is challenging. Here, a cheap handheld device was developed to realize on-site detection of disease biomarkers by Nd3+/Yb3+ co-doped near-infrared (NIR)-to-NIR downconversion nanoparticles (DCNPs) based LFA. Its sensitivity is at least 8-fold higher for detecting NIR light signal from Nd3+/Yb3+ co-doped nanoparticles than conventional expensive InGaAs camera based detection platform. Additionally, we enhance NIR quantum yield of Nd3+/Yb3+ co-doped nanoparticles up to 35.5% via simultaneous high dopant of sensitizer ions Nd3+ and emitter ions Yb3+. Combination of NIR-to-NIR handheld detection device and ultra-bright NIR emitting NaNbF4:Yb60%@NaLuF4 nanoparticle probe allows the detection sensitivity of SARS-CoV-2 ancestral strain and Omicron variants specific neutralizing antibodies LFA up to the level of commercial enzyme linked immunosorbent assay kit. Furthermore, by this robust method, enhanced neutralizing antibodies against SARS-CoV-2 ancestral strain and Omicron variants are observed in healthy participants with Ad5-nCoV booster on top of two doses of inactivated vaccine. This NIR-to-NIR handheld platform provides a promising strategy for on-site evaluating protective humoral immunity after SARS-CoV-2 vaccination or infection.

Optically stimulated electron paramagnetic resonance: Simplicity, versatility, information content

A simple technique for observing optically stimulated electron paramagnetic resonance (OSEPR) is proposed and investigated. The versatility and information content of the described technique is demonstrated by the example of the OSEPR spectra of systems that are unpopular for this type of spectroscopy: a crystal with rare-earth ions Nd3+ and a doped semiconductor GaAs. In addition, the OSEPR spectrum of atomic cesium is presented, in which an optical nonlinearity is observed that makes it possible to estimate the Rabi frequency for the relevant optical transition. The effects observed in the described experiments (switching of peaks to dips, light-induced splitting of the OSEPR lines, and the appearance of a spectral feature at the double-Larmor frequency) are interpreted using the model proposed in the theoretical part of the work. The suggested interpretation shows the possibility of using the described OSEPR technique to estimate not only ‘magnetic’ parameters of the model Hamiltonian (g-factors, spin relaxation times), but also the Rabi frequencies characterizing optical transitions.

Керамические радиационно стойкие сцинтилляторы для регистрации высокоэнергетического излучения

Complex oxides of Y3Al5O12, Gd(Nb,Ta)O4, (Zr,Hf,Y)O2, (Zr,Y)O2, activated with trivalent rare earth ions Nd3+, Eu3+ and Tb3+ have been studied in terms of their luminescent properties. These materials are promising scintillators with high radiation, chemical, and mechanical stability. The aim of the work was to develop ceramic radiation-resistant scintillators based on oxides activated by rare-earth ions. The study included: an evaluation of changes in the intensity and kinetics of luminescence decay from single crystal samples to ceramics; a study of the complete or partial replacement of light elements by heavier ones effect on the luminescent properties; a study of the possibility of using a sensitizer to increase the luminescence yield when luminescence is excited by an electron beam of medium energies.

Nd-Gd–Platinum doped TiO2 nanotube arrays catalyst for water splitting in Alkaline Medium

The utilization of a highly efficient electrocatalyst for the hydrogen evolution reaction (HER) plays an important role in energy conversion in regard to the development of hydrogen-based clean energy sources. The HER in alkaline media by co-doped lanthanide-platinum TiO2 Nanotube Arrays (TNTA) catalyst electrodes has yet to be studied. Here, we report the robust fabrication of an electrocatalyst and its prominent performance in catalyzing the HER. The catalyst electrode consisted of TiO2 nanotube arrays doped with rare earth metals (neodymium (Nd) and gadolinium (Gd)) and a small loading of Pt metal as double-layer nanotube arrays. This material was obtained by a two-step electrochemical anodization method using a small amount of fluoride salt and a short time of mechanical growth. Additionally, an in situ doping strategy that utilized a hydrothermal treatment for the ternary and quaternary ions of Nd, Gd and Pt was performed, while retaining the anatase phase. The Nd-Gd-TNTA catalyst electrode produced a current density of −47.522 µA cm−2 and exhibited a low activation energy of approximately 2.15 kJ/mol. The Nd-Gd-Pt-TNTA catalyst electrode is the best candidate for supporting the HER and advancing water splitting techniques for high-purity hydrogen production in alkaline media.

Optical switching a photon-avalanche-like mechanism in NdAl3(BO3)4 particles excited at 1064 nm by an auxiliary beam at 808 nm.

In recent years, an unconventional excitation of trivalent neodymium ions (N d 3+) at 1064nm, not resonant with ground-state transitions, has been investigated with the unprecedented demonstration of a photon-avalanche-like (PA-like) mechanism, in which the temperature increase plays a fundamental role. As a proof-of-concept, N d A l 3(B O 3)4 particles were used. A consequence of the PA-like mechanism is the absorption enhancement of excitation photons providing light emission at a broad range covering the visible and near-infrared spectra. In the first study, the temperature increase was due to intrinsic nonradiative relaxations from the N d 3+ and the PA-like mechanism ensued at a given excitation power threshold (P t h ). Subsequently, an external heating source was used to trigger the PA-like mechanism while keeping the excitation power below P t h at room temperature. Here, we demonstrate the switching on of the PA-like mechanism by an auxiliary beam at 808nm, which is in resonance with the N d 3+ ground-state transition 4 I 9/2→{4 F 5/2,2 H 9/2}. It comprises the first, to the best of our knowledge, demonstration of an optical switched PA, and the underlying physical mechanism is the additional heating of the particles due to the phonon emissions from the N d 3+ relaxation pathways when exciting at 808nm. The present results have potential applications in controlled heating and remote temperature sensing.

Assessment of the Capability of Magnetic Nanoparticles to Recover Neodymium Ions from Aqueous Solution

Magnetic nanoparticles (MNPs) have received increasing attention for various applications due to their fast synthesis, versatile functionalization, and recyclability by the application of a magnetic field. The high surface-to-volume ratio of MNP dispersions has suggested their use as an adsorbent for the removal of heavy metal ions. We investigated the applicability of MNPs composed of a maghemite core surrounded by a silica shell functionalized with aminopropylsilane, γ-Fe2O3-NH4OH@SiO2(APTMS), for the removal of neodymium ions (Nd3+) from aqueous solution. The MNPs were characterized for their size, composition, surface functionality and charge. Despite of the promising properties of MNPs, their removal from the aqueous dispersion with an external magnet was not sufficient to reliably quantify the adsorption of Nd3+ by UV-Vis spectroscopy.

The Coming of Age of Neodymium: Redefining Its Role in Rare Earth Doped Nanoparticles.

Among luminescent nanostructures actively investigated in the last couple of decades, rare earth (RE3+) doped nanoparticles (RENPs) are some of the most reported family of materials. The development of RENPs in the biomedical framework is quickly making its transition to the ∼800 nm excitation pathway, beneficial for both in vitro and in vivo applications to eliminate heating and facilitate higher penetration in tissues. Therefore, reports and investigations on RENPs containing the neodymium ion (Nd3+) greatly increased in number as the focus on ∼800 nm radiation absorbing Nd3+ ion gained traction. In this review, we cover the basics behind the RE3+ luminescence, the most successful Nd3+-RENP architectures, and highlight application areas. Nd3+-RENPs, particularly Nd3+-sensitized RENPs, have been scrutinized by considering the division between their upconversion and downshifting emissions. Aside from their distinctive optical properties, significant attention is paid to the diverse applications of Nd3+-RENPs, notwithstanding the pitfalls that are still to be addressed. Overall, we aim to provide a comprehensive overview on Nd3+-RENPs, discussing their developmental and applicative successes as well as challenges. We also assess future research pathways and foreseeable obstacles ahead, in a field, which we believe will continue witnessing an effervescent progress in the years to come.

Investigation of ion-ion (Nd–Nd) interaction mechanisms in Sr3LaNb3O12:Nd3+ crystals

The spectral-kinetic characteristics of Nd3+ optical centers (A, B, C centers) in Sr3LaNb3O12 crystals are studied by selective laser spectroscopy technique. It is found that the luminescence decay of A centers (donors) at the first stage is quenched by an ordered ensemble of acceptors (B centers) while the second stage is disordered and follows the Förster law.The macro-(γ(N1) = 55 cm−1/2, γ(N2) = 95 cm−1/2) and microparameters (CDA = 4.5⋅10−40 cm6/s) of the ion–ion (Nd3+–Nd3+) interaction are calculated using the static quenching theory. The closest distance between neodymium ions involved into the ion–ion (A and B optical centers) interaction is calculated to be Rmin. = 0.45 nm, and the boundary time at which the ordered luminescence quenching stage changes for disordered one is determined as tbound. ∼19 μs. It is shown that the A centers luminescence quenching mechanism is the dipole–dipole (S = 6) one.The Nd3+ luminescence build-up and decay kinetics in ensemble of acceptor centers (B centers) in case of unequal donor and acceptor lifetimes (τD <τA) are determined.

Titanium Nanoparticles Modified NIR Emission of Neodymium Doped Magnesium Zinc-Sulfophosphate Glass: Effect of Heat Treatment on Surface Plasmon Resonance Bands

New type plasmonic sensitizer, titanium nanoparticles (Ti NPs) shown potential in enhancing photoluminescence of rare-earth ions (REIs) as doped into magnesium zinc-sulfophosphate (MZS) glass for optical to optic application. Here, neodymium ions (Nd3+)-doped MZS glass with Ti NPs inclusion gone heat treatment (HT) at 450°C for 6 and 12 hours in order to tune the NPs size and tailor their plasmonic strength. The sample was characterized using X-ray diffractometer (XRD), high-resolution transmission electron microscope (HRTEM), and photoluminescence (PL) spectrometer. Heat treatment (HT) grows Ti NPs with a mean size ≈ 16 nm. The SPR bands are probed around 585and 739 nm. The SPR band intensities change with HT duration. The NIR PL bands were perceived around 878 nm, 1050 nm and 1322 nm corresponding to 4F3/2→4I9/2, 4F3/2→4I11/2 and 4F3/2→4I13/2 transitions, accordingly. The PL transition 4F3/2→4I9/2 (878 nm) and 4F3/2→4I13/2 (1322 nm) is enhanced about 1.44 and 1.52 times respectively, after 12 hours HT. The results show that HT enhances PL through SPR amplification. These findings may be useful in developing solid-state lasers and optical materials.

Random lasing and replica symmetry breaking in GeO2-PbO-MgO glass–ceramics doped with neodymium

We investigated the random lasing process and Replica Symmetry Breaking (RSB) phenomenon in neodymium ions (Nd3+) doped lead-germanate glass–ceramics (GCs) containing MgO. Glass samples were fabricated by conventional melt-quenching technique and the GCs were obtained by carefully devitrifying the parent glasses at 830 °C for different time intervals. The partial crystallization of the parent glasses was verified by X-ray diffraction. Photoluminescence (PL) enhancement of approx 500% relative to the parent glasses was observed for samples with a higher crystallinity degree (annealed during 5 h). Powders with grains having average size of 2 µm were prepared by griding the GCs samples. The Random Laser (RL) was excited at 808 nm, in resonance with the Nd3+ transition 4I9/2 → {4F5/2, 2H9/2}, and emitted at 1068 nm (transition 4F3/2 → 4I11/2). The RL performance was clearly enhanced for the sample with the highest crystallinity degree whose energy fluence excitation threshold (EFEth) was 0.25 mJ/mm2. The enhanced performance is attributed to the residence-time growth of photons inside the sample and the higher quantum efficiency of Nd3+ incorporated within the microcrystals, where radiative losses are reduced. Moreover, the phenomenon of Replica Symmetry Breaking (RSB), characteristic of a photonic-phase-transition, was detected by measuring the intensity fluctuations of the RL emission. The Parisi overlap parameter was determined for all samples, for excitation below and above the EFEth. This is the first time, for the best of the authors knowledge, that RL emission and RSB are reported for a glass–ceramic system.