Erbium Concentration Research Articles

Synthesis and Characterization of Erbium-Doped Silica Films Obtained by an Acid-Base-Catalyzed Sol-Gel Process.

Erbium-doped silica films were synthesized using a two-step sol-gel methodology that involved acid and base catalysts, with erbium concentration ranging from 0.2% to 6% and annealing temperatures varying from 500 °C to 900 °C. The photoluminescence spectra showed that the samples exhibiting efficient emission were annealed at 800 °C and 900 °C and doped with 3% and 6% erbium. The X-ray diffraction analysis revealed that the internal structure of the films was influenced by the different annealing temperatures and the doping concentrations. Samples with dominant 4f transitions were modelled. The results suggest that the proposed method is a promising approach for the synthesis of erbium-doped silica films with potential applications in optical devices.

Luminescence biomonitoring and antibacterial properties of Er3+-doped SiO2–CaO–P2O5 bioactive glass microspheres

Mesoporous bioactive glasses have great potential for applications in the field of bone tissue repair due to their excellent biological properties, but effective information on the repair process is not available in a timely manner. Thus, real-time monitoring of mineralization and drug release processes will be beneficial to obtain the degree of healing and optimize the amount and distribution of drugs to improve targeted therapeutic effects. Here, erbium-doped mesoporous bioactive glass microspheres (Er/MBGs) were successfully synthesized by the sol-gel method, and the doping concentration of erbium was selected based on fluorescence, BET, and bioactivity tests. The results showed that 4Er/MBGs not only had the highest luminescence emission, higher specific surface area (418.8 m2/g) and mesopore volume (0.42 cm3/g) but also presented excellent bioactivity. Therefore, 4Er/MBGs were selected for in vitro real-time monitoring of mineralization and drug release. It has been shown that the luminescence intensity of 4Er/MBGs is linearly related to its mineralization degree; As the degree of mineralization increases in vitro, the intensity of the luminescence emission gradually decreases. The results of in vitro drug release monitoring experiments showed that 4Er/MBGs loaded with the anticancer drug doxorubicin (DOX) exhibited great pH responsiveness, and the loaded DOX selectively quenched the green emission of the microspheres. When the drug was released, the green emission recovered stably, and the signal value of the ratio R (I650 nm/I510 nm) of the emission intensity of the red to the green of the microspheres gradually decreased. Monitoring changes in the value of the R signal is instructive for tracking the drug release process. Meanwhile, in vitro antibacterial experiments indicated that 4Er/MBGs had a strong inhibitory effect on E. coli and S. aureus, with antibacterial rates of up to 92.5% and 90.7%, respectively. Collectively, Er/MBGs have potential applications as optically functional materials in bone tissue engineering.

Исследование свойств монокристаллов ниобата лития одинарного и двойного легирования — функциональных материалов оптоэлектроники

A series of six LiNbO3:Tb ([Tb] = 0.1 — 2.89 wt%) crystals and seven LiNbO3:Er ([Er] = 0.08÷2.71 wt%) crystals were grown according to a single methodology. Optical uniformity and optical resistance were compared in LiNbO3:Tb and LiNbO3:Er of various chemical composition. The periods of the crystal lattice were determined by the methods of a full -profile analysis of the XRD patterns of polycrystals; models of the atomic structure of LiNbO3:Tb and LiNbO3:Er crystals were analyzed with a change in the dopant concentration. In a series of LiNbO3:Tb crystals, a concentration threshold near the concentration of terbium ~ 2.2 — 2.3 wt% was discovered for the first time. A concentration threshold near the concentration of erbium ~ 2.4 — 2.5 wt% was discovered in LiNbO3:Er. In the area of the concentration threshold, pronounced anomalies of physicochemical, optical and structural characteristics are observed. Growth irregular and regular domain microstructures were revealed in as-grown LiNbO3:Tb and LiNbO3:Er crystals by optical and atomic force microscopy. Structural characteristics and threshold effects are studied in LiNbO3:Gd and LiNbO3:Gd,Cu crystals by Raman spectroscopy, PILS, laser conoscopy and optical microscopy. In LiNbO3:Gd crystals the photorefractive effect is suppressed at as low concentration as [Gd] = 0.05 wt%. For LiNbO3:Gd,Cu crystals a distinct photorefractive response is observed, it increases with increasing Cu concentration. The effect of the association of defects (carriers) is experimentally confirmed and thermodynamically justified by the example of oxygen-octahedron structures such as perovskite and pseudoi:lmental during ion conduction in a certain temperature interval. The discovered phenomenon is extremely important for creating and evaluating the temperature range of operability of ion current sources.

Photoluminescent Er-doped As20Se80 thin films and channel waveguides produced by thermal reflow

The chalcogenide glasses are an excellent material alternative for the poorly developed optics of the mid-infrared region on integrated photonics. Their great transmission in the IR region, the outstanding non-linear optical properties, and the recently explored possibility of processing by thermal reflow have sparked considerable interest in the fabrication of micro and nano-structures with symmetric and smooth surfaces suitable for optical components. The thermal reflow nevertheless is not useful for certain glass compositions since it induces phase separation and crystallization that compromise the optical quality. Rare earth-doped chalcogenides, of great interest for the development of laser and amplifiers, are especially prone to such dehomogenization since they have shown to be difficult to synthesize and process without obtaining fluorescence quenching caused by agglomeration and phase separation. In this work, we demonstrate for the first time that under certain conditions it is possible to induce thermal reflow in Er-doped chalcogenide thin films without inducing agglomeration and extinguishing the erbium emission. The films, produced by the co-evaporation of metallic erbium and As20Se80 glass matrix, demonstrated great molecular flexibility that allows to observe thermal reflow in films with erbium concentrations up to 0.6 at%. We use this thermal reflow in doped ridge channel waveguides (produced by photolithography) to reduce the optical losses and to enhance the fluorescence properties of the material by the rearrangement of the emitting ions. Our study opens the door for the fabrication and processing of rare earth-doped chalcogenide planar devices and their future integration into photonic circuits.

EFFECT OF ERBIUM DOPING ON PHYSICAL PROPERTIES OF LaFeO3


 
 
 Multiferroic La1-xErxFeO3 (x= 0, 0.2, 0.4, 0.6, 0.8 and 1) successfully synthesized using auto combustion sol-gel citrate method. The crystalline structure examined by X-ray Diffraction (XRD) analysis is orthorhombic. Infrared (IR) active phonons for Erbium substitution in La1-xErxFeO3 studied at room temperature in frequency range 30-1000 cm-1 via Fourier transformed infrared (FTIR) spectroscopy. The experimental reflectivity spectra has been fitted using Lorentz oscillator model and obtain the parameter like damping factor, optical frequency as well as oscillator strength. Real and imaginary part of dielectric constant, optical conductivity, loss function and energy band gap in addition to transverse and longitudinal optical frequency modes have been calculated by these parameters. The frequency shift has been observed with doping concentration of Erbium in LaFeO3. Optical conductivity spectra are of semiconducting type. La1-xErxFeO3 is further characterized by UV- visible spectroscopy and electrical resistivity measurements. The optical spectrum of UV-Visible phenomena exhibits typical semiconductor behaviour. Investigation shows there is a drop in activation energy of samples if doped element Er increases. The electrical resistivity trend shows semiconducting behaviour of the sample which exhibit p-type polaronic conduction.
 
 

Determinant of Glass Material’s Parameters for Fiber Optic Application Durability

The aim of this study was to determine the principle cause of variation in a measured glass durability using a melt-quenching method. Further goal for this study was to find the optimum level of the factor for producing the glass durability. For that purpose, One-Way Analysis of Variance (ANOVA) was performed. From the analysis, it was found that all longitudinal modulus, shear modulus 2 and shear modulus 3 were the significant parameters that produced high quality of glass durability (p<0.05). The mean analysis revealed that the best condition that maximizes the average of Longitudinal Modulus 1, 2 and 3 would be when the erbium concentration was 0.05. It was found that the erbium concentration with 0.03 produced the optimum Longitudinal Modulus 4 and 5. The findings also pointed out that the average of Shear Modulus 2 and 3 was maximized when the erbium concentration was 0.03 and 0.05, respectively.

Structural, microstructural, spectral, and dielectric properties of erbium substituted spinel ferrites

The Erbium substituted manganese spinel ferrites were prepared via the microemulsion route. The average crystallite size varies from 10.21 to 17.41 nm, while the lattice constant observes to increase from 8.473 to 8.509 Å. X-ray density increases with the incorporation of Er3+ ions in manganese ferrites. The characteristic bands lie in the range of 410–560 cm−1 which confirms the cubic structure of synthesized ferrites. The band variation is evidence of the successful substituting of Er3+ ions in manganese spinel ferrites lattices. Bond lengths increase with the increase of Er3+ content. The dielectric constant, dielectric loss, and tan loss decrease as frequency and Erbium concentration increase. Scanning electron microscopy (SEM) micrographs reveal the decrease in grain size with Er3+ in manganese ferrites. The obtained results suggested that synthesized ferries can be potential candidates for high-frequency applications.

Enhancement of spectroscopic properties of Er3+ doped TeO2-Nb2O5-ZnO glassy systems for optical amplifiers at 1.53 µm

Tellurite-based glasses doped with varying amounts of Er3+ ions were elaborated by the melt quenching process. Based on Judd-Ofelt model, the local structures around erbium ions were studied and various optical parameters such as quantum efficiency (η), radiative lifetime (τR) and quality factor (χ) were determined. Following the addition of Er2O3, the results showed an enhancement in luminescence intensity at 1530 nm as well as a significant improvement of the effective bandwidth (108.8 nm), the emission cross section (9.1 ×10−21 cm2)and the quantum efficiency (91.8%) ascribed to the emission band at 1530 nm. The impact of adding a large amount of Er2O3 on the experimental lifetime of the 4I13/2 level was analysed using the Inokuti-Hirayama model. The obtained results were correlated with the concentrations of hydroxyl groups to investigate the luminescence quenching process in the tellurite glasses and to explain the decrease in some spectroscopic parameters. Accordingly, the results indicate that TeO2-based glass which contains optimum erbium concentrations may be a suitable material in the design of wide-band optical fiber amplifiers (EDFAs).

Numerical Calculation of the Thermodynamic Properties of Silver Erbium Alloys for Use in Metallic Magnetic Calorimeters

Using dilute silver erbium alloys as a paramagnetic temperature sensor in metallic magnetic calorimeters (MMCs) has the advantage of the host material not having a nuclear quadrupole moment, in contrast to the alternative of using gold erbium alloys. We present numerical calculations of the specific heat and magnetization of Ag:Er, which are necessary for designing and optimizing MMCs using this type of alloy as sensor material. The parameter ranges we consider are temperatures between 1,{text {{mK}}} and 1,{text {{K}}}, external magnetic fields of up to 20,{text {{mT}}}, and erbium concentrations of up to 2000,{text {{ppm}}}. The system is dominated by an interplay of crystal field effects, Zeeman splitting, and the RKKY interaction between erbium ions, with certain specific constellations of erbium ions having noticeable effects on the specific heat. Increasing the external magnetic field or assuming a decreased strength of the RKKY interaction leads to a higher magnetization and a narrowing of the main Schottky peak, while changes in the erbium concentration can be well described by parameter scaling.

Erbium chloride silicate-based vertical cavity surface-emitting laser at the near-infrared communication band.

Silicon-based integrated optoelectronics has become a hotspot in the field of computers and information processing systems. An integrated coherent light source on-chip with a small footprint and high efficiency is one of the most important unresolved devices. Here, we realize a silicon-based vertical cavity surface-emitting laser in the near-infrared communication band by making efforts in both controlled preparation of high-gain erbium silicate materials and novel design of high optical feedback microcavity. Single-crystal erbium/ytterbium silicate microplates with erbium concentration as high as 5 × 1021 cm-3 are controlled prepared by a chemical vapor deposition method. They can produce strong luminescence with quite a long lifetime (2.3 ms) at the wavelength of 1.5 μm. By embedding the erbium silicate microplates between two dielectric Bragg reflectors, we construct a vertical cavity surface-emitting laser at 1.5 μm, with a lasing threshold as low as 20 μJ/cm2 and Q factor of nearly 2000. Our study provides a new pathway to achieve a sub-micrometer coherent light source for optical communication.

Erbium adsorption from aqueous solutions using RSM-based optimization of the phosphate functional group in modified nano titania

Nano-titania was modified by nitrilotris(methylene)phosphonic acid (NTMP) as a new adsorbent and as a suitable linker for further performance to the adsorption of erbium from aqueous solutions. The adsorbent was characterized by different techniques analysis including FTIR, BET, SEM, XRD and XPS. The effects of adsorbent dose, pH, initial concentration of erbium and temperature were optimized by central composite design (CCD) and were analyzed and modeled by response surface methodology (RSM). Statistical analysis of variance (ANOVA) was carried out to identify the adequacy of the developed model, and revealed good agreement between the experimental data and proposed model. The adsorption capacity of erbium in pure nano titania, NTMP/nano titania and optimal adsorption conditions was 12.5 mg g−1, 50 mg g−1 and 106 mg g−1, respectively. In this work, we showed that phosphate group from NTMP how could modified the adsorbent surface. Moreover, the kinetic and isotherm studies were conducted. Regarding to the calculation of ΔG°, ΔH° and ΔS°, it is observed that the nature of erbium ion sorption was endothermic, spontaneous, physisorptive and was favored at higher temperature. Furthermore, the desorption capacity of erbium ions by H3PO4, HCl, HNO3, H2SO4, and EDTA was evaluated. Finally, the presence of competitive ions (La3+, Sm3+, and Dy3+ ions) on the erbium adsorption capacity was investigated using RSM. Considering all these, we show that the novel adsorbent can be effective for the removal of erbium from aqueous solutions using sorbent modified technique.

Enhanced upconversion luminescence and optical temperature sensing performance in Er3+ doped BaBi2Nb2O9 ferroelectric ceramic

A series of BaBi 2- x Nb 2 Er x O 9 ceramic compositions with different Er 3+ concentration ( x = 0.0–8 mol %) is synthesized by a conventional solid-state reaction method. The upconversion (UC) light emission under 980 nm excitation with different pump powers and luminescence-based temperature sensing ability of BaBi 2- x Nb 2 Er x O 9 composition have been examined. The formation of a Bi-layered perovskite phase of BaBi 2 Nb 2 O 9 is confirmed having an orthorhombic geometry and Fmmm space group. Shifts in the Raman modes indicate reduced interaction of Bi 3+ ions with NbO 6 octahedron leading to relaxation of structural distortion with increasing Er 3+ content. The maximum value for remnant polarization and coercive field of doped BaBi 2- x Nb 2 Er x O 9 ceramic for ( x = 0.08) Erbium concentration comes out to be 2.9524 μC/cm 2 and 49.8980 kV/cm. For an optimum content of x = 0.04, two strong UC green emission bands were observed at 549 nm via 4 S 3/2 → 4 I 15/2 transition and 527 nm via 2 H 11/2 → 4 I 15/2 transitions, and a weak red emission appears at 657 nm attributed to the 4 F 9/2 → 4 I 15/2 transition. Pump power dependence suggests that UC emission is a two-photon mechanism for red and green emission bands. Temperature sensing evaluated by the change in the fluorescence intensity ratio (I 527 /I 549 ) indicates the highest sensitivity to be 0.00996 K −1 at 483 K for an optimum concentration of Er 3+ at x = 0.04 in BaBi 2- x Nb 2 Er x O 9 composition and is useful for non-contact optical thermometry.

Twenty-three-millisecond electron spin coherence of erbium ions in a natural-abundance crystal.

Erbium ions embedded in crystals have unique properties for quantum information processing, because of their optical transition at 1.5 μm and of the large magnetic moment of their effective spin-1/2 electronic ground state. Most applications of erbium require, however, long electron spin coherence times, and this has so far been missing. Here, by selecting a host matrix with a low nuclear-spin density (CaWO4) and by quenching the spectral diffusion due to residual paramagnetic impurities at millikelvin temperatures, we obtain a 23-ms coherence time on the Er3+ electron spin transition. This is the longest Hahn echo electron spin coherence time measured in a material with a natural abundance of nuclear spins and on a magnetically sensitive transition. Our results establish Er3+:CaWO4 as a potential platform for quantum networks.

Photoluminescence Study of Up-Conversion Phosphor La2(MoO4)3 Yb3+, Er3+ Prepared by Precipitation Method

Up-conversion phosphors of La 2 (MoO 4 ) 3 : Yb 3+ , Er 3+ with different concentration of Erbium were prepared by a simple precipitation method. The crystal structure, surface morphology, elemental composition, and photoluminescence properties were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDAX) and Photoluminescence spectroscopy respectively. XRD spectra show a high degree of crystallinity in all samples. SEM images show rod-like structures present in the samples. EDAX analysis confirms the presence of dopants (Yb 3+ and Er 3+ ) in the host matrix (La 2 (MoO 4 ) 3 ). Upon excitation by 980 nm infrared radiation, all the samples give emission peaks between 524 – 533 nm in the bluish-green region, 546 – 555 nm in the green region and 659 – 672 nm in the red region which are attributed to the 2 H 11/2 → 4 I 15/2 , 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 transitions of Er 3+ ions respectively.

Influence of Boron anomaly on the NIR fluorescence concentration quenching of erbium ions in borate glasses

Constructing the glass matrix to avoid the concentration quenching is significant to obtain heavily doping and higher optical gain glasses. In this work, B2O3-Na2O binary glasses with different O/B were employed for discussing the relationship between the glass structure and erbium ions concentration quenching. The Raman spectra indicated that when the O/B was 0.16, the [BO3] would be mostly transformed into [BO4] in the glass network, and furtherly increased O/B, the [BO3] would not be transformed into [BO4] continuously. The critical doping concentration was highest when the O/B was 0.16, which suggested that the relative complete framework structure would be beneficial to obtain homogenously distribution of rare earth ions. Lower O/B, more diverse of the glass structure units, which would be favor to obtain broadband width of NIR fluorescence of Er3+ ions.

1.53 μm luminescent properties of Er3+-doped fluoroaluminate glasses

The Er3+ doped fluoroaluminate glasses were prepared by melt quenching technique and characterized through spectroscopic methods. The concentration of erbium ions was 0.1, 0.5 and 1.0 mol %. Luminescence spectra with a maximum of about 1.53 μm were obtained with excitation at a wavelength of 975 nm. Based on measurements in the integral sphere, it was found that with an increase in the concentration of erbium ions, the intensity of the luminescence band increases. The absorption (4I15/2 → 4I13/2) and emission (4I13/2 → 4I15/2) cross-sections were calculated using McCumber theory. The peak value of emission cross-section was 5.30 × 10−21 cm2 and the gain bandwidth value was 243 × 10−28 cm2. The calculated gain/loss spectra at different population inversion values suggest that, the fluoroaluminate glasses possess amplification in C and L spectral bands starting from 45% population inversion. The obtained results reveal that glasses of investigated composition are candidates for optical fiber amplifiers and laser sources operated at 1.5 μm.

Judd-Ofelt analysis of spectroscopic measurements of Er3+ doped boro-zincate glasses

• Combined spectral and thermal measurements of high zinc borate glasses doped with different concentrations of Er3+ ions were carried out for investigation this system to be used in optical devises. Glasses based on the base composition (ZnO 70 – B 2 O 3 30 mol %) containing increasing Er 2 O 3 as dopant (0.2 → 2.2 mol%) were synthesized by traditional melting. Collective investigation was done through measuring their UV-visible and structural FTIR spectra. The density and derived physical properties were calculated in relation to the constitution and percent of rare-earth oxide. Optical absorption studies show specific and characteristic peaks which are correlated with the absorption of Er 3+ originated from the ground state 4 I 15/2 to several possible energy transitions. Structural IR data indicate distinct and extended bands from 400-1600 cm −1 which are assigned to the two known characteristic borate units with triangular and tetrahedral coordinations (BO 3 , BO 4 ). The possible forming of ZnO 4 is considered due to the abundance of ZnO (70 mol%) but the intensities of the vibrations of the two borate units are distinctively higher due to the known lightest boron element which is reflected on its oxide (B 2 O 3 ) than other glass forming oxides. The IR spectra have been confirmed by the measurements of the IR spectrum of pure crystalline ZnO to elucidate its specific vibrational sites. The density and molar volume data are correlated with the trivalent erbium ions concentration and their housing in the glass structure. The various optical parameters of the Er 2 O 3 -doped glasses were derived and analyzed in relation to the concentration of Er 3+ ions.

Photoconduction of nanoparticle arrays pumped with near 1550 nm pulse lasers

When erbium (Er) concentration is greater than ∼7 × 1017/cm3, ErAs nanoparticles with various sizes are formed spontaneously in GaAs epitaxial layer during MBE growth. This letter presents experimental studies on transient photoconduction of ErAs nanoparticle arrays when pumped by laser pulses with wavelengths near 1550 nm. The experimental data suggests the photoconduction may be contributed by two mechanisms. One is extrinsic photoconductivity, where bound electrons from levels of nanoparticles pinned near the middle of GaAs forbidden gap transfer to the conduction band of GaAs (i.e. bound to conduction band). The other is displacement-current conduction traced to photon-assisted polarization of nanoparticles with two quantized energy levels. This investigation explains why these nanoparticle-embedded materials have a higher responsivity to pulsed lasers than continuous wavelength (CW) lasers.

Manipulation of Molecular Vibrations on Condensing Er3+ State Densities for 1.5 μm Application.

Vibrational modes of chemical bonds in organic erbium (Er3+) materials play an important role in determining the efficiency of the 1.5 μm Er3+ emission. This work studies the energy coupling of the Er3+ intra-4f transitions and vibrational modes. The results demonstrate that the coupling introduces enormous nonradiative internal relaxation, which condenses the excited erbium population on to the 4I13/2 state. This suggests that vibrational modes can be advantageous for optimizing the branching ratio for the 1.5 μm transition in organic erbium materials. Through control of the quenching effect on to the 4I13/2 state and a reliable determination of intrinsic radiative rates, it is found that the pump power for population inversion can be reduced by an order of magnitude at high erbium concentrations compared to conventional inorganic erbium materials.

Temperature sensing down to 4 K with erbium-doped tellurite glasses

Two binary tellurite glasses within TeO2–PbCl2–WO3 system with different concentrations of Er3+ ions were prepared by the conventional melt-quench technique and their optical properties were compared with emphasis on their potential use for temperature sensing starting from 4 K. Therefore, absorption and emission spectroscopy was used to determine the emission properties of Er3+ in the visible and near-infrared regions across a wide temperature range of 4-300 K. Photoluminescence emissions resulting from direct absorption or frequency up-conversion were measured across a wide temperature range and their dependence on the concentration of erbium ions and on excitation power density were studied in detail. It was demonstrated that by optimizing concentration of erbium ions, the luminescence intensity ratio of suitably selected thermally coupled/uncoupled levels and their Stark sublevels can be used for the non-contact optical temperature sensing at cryogenic temperatures.