Erbium Concentration Research Articles

Structural, optical, and photoluminescence properties of erbium doped TiO2 films

TiO2 thin films doped with low percentages (3, 7, and 10 at.%) of Er3+ have been synthesized by sol gel spin coating technique. The influence of erbium concentration on the physical properties was analyzed using different characterization techniques such as X-ray diffraction, Raman spectroscopy, TEM analysis, EDS-SEM, AFM, UV–Visible transmittance spectroscopy, photoresponse and photoluminescence. The doped films exhibited significant modifications on the structural, optical and electrical properties due to the incorporation of erbium ions. The band gap energy was red shifted by Er doping indicating an improvement in visible light absorption. Intense Er3+-based emission peaks in the range 520–560 nm were observed for all samples. It was observed that Er-dopant concentration had direct impact on photoluminescence intensity.

Production of Un-Doped and Er-Doped Y2O3 Thin Films by Electron Beam Evaporation Method

In this study, un-doped and doped yttrium oxide (Y2O3) powders with different erbium concentrations were synthesized using sol-gel method. The synthesized powders were investigated by Raman analysis and the evolution of different peaks associated with Er dopant in Y2O3 structure was clearly observed. Moreover, the powders were deposited on Corning glasses using electron beam (e-beam) evaporation method. The samples were heat-treated at 300 and 400°C temperatures for 6 h. The effects of the heat treatment temperatures and dopant concentrations on the optical properties were investigated. Phase constituents of the thin films were analyzed by X-ray diffraction with a thin film attachment using Cu-Kα radiation. Optical transmittance curves of the films were measured using optical spectrophotometer. Cross sectional morphologies of the films were examined using scanning electron microscopy (SEM). It was observed that Er dopants caused a shift in the transmittance curves to UV region.

Er3+-doped niobium alkali germanate glasses and glass-ceramics: NIR and visible luminescence properties

Niobium alkali germanate glasses doped with Er3+ up to 4.0 mol% were synthesized by the melt-quenching technique. Glass-ceramics were obtained by controlled heat treatment of the pristine glass. Thermal and optical properties were investigated and are shown to depend on the erbium content. The main radiative parameters were obtained based on the Judd-Ofelt theory. The change of radiation energy processes and modification of the environment of the earth-rare ion occurs in samples with high erbium concentrations. In general, strong enhancement of upconversion emission occurs due to the efficient process of excited-state absorption for the high erbium content samples. Visible tunable phosphors emitting either red-to-green light depends on the erbium content and heat treatment. In addition, these glasses and glass-ceramics samples have high thermal stability and wide transmission window. For these reasons, Er3+-doped niobium germanate glasses and glass-ceramics may be suitable for photonic device applications, especially as visible laser.

Investigations of the effect of trivalent erbium concentration on orthophosphate powder for green and yellow-orange light emitting phosphor

Lately, interesting features of lighting Rare Earths doped phosphorus have gained much attention and became favorite research matter among various groups of scientists. In this context, polycrystalline powders of Na3La(PO4)2: Er (0%, 2,5%) have been prepared by the solid state method. Powder X-ray diffraction, infrared spectroscopy have been used to identify these materials. The spectroscopic properties of Na3La(PO4)2: Er (2,5%) have been investigated through absorption, excitation, emission spectra and decay curves of Er3+ at room temperature. The decay time reveal that Na3La(PO4)2: Er (2,5%) possesses a radiative transition and the lifetime value for the transition 4F9/2 → 4I15/2 is found equal to 144.92 μs. All obtained results have been presented, compared and discussed with last reported works. The CIE chromaticity coordinates have been highlighted. They reveal that Na3La(PO4)2: Er (2,5%, 10%, 20% and 50%) phosphor can be a promising green and yellow-orange luminophore for application in LED.

Effect of the Trivalent Erbium Concentration on the Luminescent Properties of TiO2 Er3+ Composites

In this work we synthetized Er3+-doped TiO2 composites by means of the sol-gel method aiming to find the most emissive sample. For this optical characterization we used three samples with different erbium concentration (0.5, 1.0 and 3.0 wt%). We measured and compared the corresponding photoluminescent emission spectra using an excitation wavelength at 350 nm. Emission peaks in the green region associated with Er3+ transitions 4S3/2  4I15/2 and 2H11/2 4I15/2 were found. The sample TiO2Er1 (1.0 wt%) had the highest intensity profile and therefore we performed further characterizations on this composite. We measured its emission spectrum in the infrared region using the same excitation at 350 nm and we found emission peaks associated with transitions 4I11/2  4I15/2 and 4I13/2  4I15/2. We verified the morphology and structural properties of this material with Raman spectroscopy, X-Ray Diffraction and Scanning Electronic Microscopy. We consider that this composite could have promising potential in applications in communications.

Effect of the Erbium Concentration in the Luminescent Properties of ZrO2

In this work, an analysis of the luminescent properties of zirconium oxide (ZrO 2 ) doped with Er 3+ in three different concentrations was performed to investigate which sample could be useful for optoelectronic applications. To achieve it, a set of four samples of ZrO2:Er 3+ with the variation in Er 3+ concentration about 0%, 0.1%, 0.2% y 0.3% were synthesized by the sol-gel method. The luminescence measurements for all samples were performed using an excitation wavelength of 380 nm, by this way the upconversion spectrum for the sample containing the 0.2% of Er 3+ was measured at 980 nm. The luminescence spectra showed three emission bands attributed to the electronic transitions 4 F 7/2 → 4 I 15/2 , 2 H 11/2 → 4 I 15/2, and 2 S 3/2 → 4 I 15/2 , all this band belonged to Er 3+ radiative transitions, we found that the sample with 0.2% presented a higher emission intensity at 550 nm compared with the others samples, also the average lifetime was calculated, we found that this value decrease with the increment of Er 3+ concentration, finally, the upconversion spectrum were measured for the sample with higher luminescent intensity at 380 nm, the result revealed that the most probable emission after the photon absorption is that around 550 nm.

Electrostatic Origin of Element Selectivity during Rare Earth Adsorption.

Rare earths, which are fundamental components of modern technologies, are often extracted from aqueous solutions using surfactants at oil-water interfaces. Heavier lanthanides are more easily extracted, even though all lanthanides are chemically very similar. Using x-ray fluorescence measurements and theoretical arguments, we show that there is a sharp bulk-concentration-dependent transition in the interfacial adsorption of cations from aqueous solutions containing Er^{3+} or Nd^{3+} in contact with a floating monolayer. The threshold bulk concentration of erbium (Z=68) is an order of magnitude lower than that of neodymium (Z=60), and erbium is preferentially adsorbed when the solution contains both ions. This implies that elemental selectivity during separation originates at the surfactant interface. Electrostatic effects arising from the interface dielectric mismatch, ionic correlations, and sizes of the ions explain the sharp adsorption curve and selectivity.

Erbium luminescence in (Y, Er, Yb)3Al5O12 powders

In this work, the Stokes and anti-Stokes luminescence (upconversion) of erbium in powders of yttrium-aluminum garnet with various concentrations of erbium, as well as co-doped with erbium and ytterbium, synthesized by the sol-gel method using multistage thermal processing, was investigated. It was established that the phase composition of the resulting powders corresponds to the crystal structure of garnet. For all powders, high-intensity Stokes luminescence with a maximum at 1.53 μm was observed due to the I13/24→I15/24 electronic transition, and anti-Stokes luminescence was observed with the most intense band in the region of 0.65–0.69 μm, associated with the F9/24→I15/24 transition of Er3+ ions. The highest intensity of the Stokes luminescence is observed for the maximum substitution of yttrium by erbium considered here, which corresponds to the Yb1.5Er1.5Al5O12 stoichiometry. The highest intensity of the anti-Stokes luminescence is for the lowest erbium concentration and for codoping with ytterbium with Y2.71Er0.29Al5O12 and Y2Er0.5Yb0.5Al5O12 stoichiometries, respectively.

3.42 µm lasing in heavily-erbium-doped fluoride fibers.

In this paper, we investigate laser emission at 3.4μm in heavily-erbium-doped fluoride fibers using dual-wavelength pumping. To this extent, a monolithic 7 mol% erbium-doped fluoride fiber laser bounded by intracore fiber Bragg gratings at 3.42 μm is used to demonstrate a record efficiency of 38.6 % with respect to the 1976 nm pump. Through numerical modeling, we show that similar laser performances at 3.4 μm can be expected in fluoride fibers with erbium concentrations ranging between 1 - 7 mol%, although power scaling should rely on lightly-doped fibers to mitigate the heat load. Moreover, this work studies transverse mode-beating of the 1976 nm core pump and its role in the generation of a periodic luminescent grating and in the trapping of excitation in the metastable energy levels of the erbium system. Finally, we also report on the bistability of the 3.42 μm output power of the 7 mol% erbium-doped fluoride fiber laser.

Study of Dilute CuEr Alloys by the EPR Method

The spectrum of the electron paramagnetic resonance of the Er3+ ion in the matrix of metallic copper has been studied at 9.8 GHz in the temperature range from 1.7 to 4.2 K. The spectrum corresponds to the crystal field of cubic symmetry at g = 6.805 ± 0.01; this value agrees with the expected value for the doublet Γ7. The residual width of the EPR line (T = 0 K) for the even isotopes of erbium was only 4.5 Oe. The temperature and concentration changes in the width of the line indicate the existence of an RKKY interaction between erbium ions. The hyperfine structure (HFS) of the EPR line for the 167Er isotope has been identified. The positions of separate HFS lines are described with an accuracy of 1.5 Oe by a constant A = 74.25 ± 0.1 Oe. The increase in the accuracy of the determination of the hyperfine splitting of lines of the Er3+ ions made it possible to reveal a weak exchange narrowing of the HFS upon an increase of the erbium concentration in these alloys.

Влияние химического состава кристаллов TlIn-=SUB=-1-x-=/SUB=-Er-=SUB=-x-=/SUB=-S-=SUB=-2-=/SUB=- (0≤ x≤0.01) на их диэлектрические характеристики и параметры локализованных состояний

The frequency dependences of the real (ε) and imaginary (ε ″) components of the complex dielectric constant, tangent of dielectric loss (tan) and ac conductivity (σac) of the obtained TlIn1-хErхS2 (0  x  0.01) crystals have been studied in the frequency range f = 5104–3.5107 Hz. It is established that in TlIn1-хErхS2 a relaxation dispersion of ε and ε″ takes place. The effect of erbium concentration (Er) in TlIn1-хErхS2 crystals on their dielectric coefficients was studied. In the high frequency range, the ac conductivity of TlIn1-хErхS2 crystals obeyed the σac ~ f 0.8 law, which is characteristic of a hopping charge transfer mechanism at states localized near the Fermi level. The parameters of states localized in the band gap and the influence of the chemical composition of the TlIn1-хErхS2 crystals on these parameters are estimated.

Optimization of Concentration Quenching on Erbium Ytterbium Doped Wave Guide EYDWA Using for Extended Reach up to 160 Km of Hybrid Gigabit Passive Optical Networks and Free Space Optical Technologie “GPON-FSO”

Abstract The purpose of this paper is to demonstrate an implementation of Er3+/Yb3+ codoped glass waveguide amplifiers (EYDWA) as a post-amplifier can provide an extended reach and a high split-ratio for the cost-effective implementation of hybrid fiber-to-the-x (FTTx) and free space optical (FSO) technologies. The performance has been compared on the basis of transmission distance, however the results of simulation show enhancement offered by EYDWA. This amplifier was able to reach transmission distance ratio of 160:5 km for GPON:FSO. Moreover in this paper, was study different characterizations of EYDWA amplifier, which depend essentially on the opt-geometric parameters, such as concentrations of ions erbium, length of the waveguide amplifier and the effect of those parameters to optimize the gain G, quality factor Q, min of BER and eye diagram.

Possibilities of laser amplification and measurement of the field structure of ultrashort pulses in the range of 2.7 – 3μm in tellurite glass fibres doped with erbium ions

The amplification of ultrashort signals in the range 2.7 – 3 μm in active tellurite glass fibres with high Kerr nonlinearity and high concentration of erbium ions in the core is theoretically investigated under diode pumping at a wavelength of 0.975 μm. The possibility of producing pulses with the energy ∼10 nJ and the duration smaller than 100 fs with ∼20 dB gain is shown. Moreover, using a specially developed iterative computer algorithm, the possibility of determining the intensity and phase of the generated pulses by measuring their fundamental spectra and two additional spectra obtained by means of nonlinear-optical conversion in short pieces of these optical fibres is demonstrated. Optical fibre samples are made of high-purity TeO2 – ZnO – La2O3 – Na2O glasses with 1021 cm−3 concentration of erbium ions in the core and a low content of hydroxyl groups that causes small losses in the spectral range under consideration. The group velocity dispersions, effective mode fields, nonlinear coefficients and field overlap integrals of the LP01 fundamental modes with a doped core for optical fibres with different core diameters are calculated, and the emission and absorption cross sections are calculated basing on the experimental luminescence spectrum. The optimal parameters of the amplifier are determined by numerically modelling the dynamics of ultrashort pulses using the measured and calculated characteristics.

Ring-Type Erbium-Doped Antiresonant Reflecting Optical Waveguide Amplifier Analysis and Design

Erbium-doped antiresonant reflecting optical wave- guides (ARROWs) allow combining wavelength selective guiding due to their attractive spectral versatility with an active operation. In this letter, the analysis and design of a ring-type erbium-doped ARROW amplifier is presented. The influence of the involved passive and active parameters (ring thickness and diameter, refractive index variation, pump and signal wavelengths, Er3+-ion concentration, and input pump power) on the spectral response of the structure and the optical power propagation losses and on the amplifier performance is numerically analysed. The opposite influence of the ring diameter on the optical power confinement and on the pump power density causes the existence of a diameter value that maximizes the amplifier net gain. For a cladding refractive index of 1.4 and moderate index variations, $\Delta n = 0.2 -0.4$ , the optimum ring diameter is in the range of 20 $\mu \text{m}$ . To compensate signal confinement losses (a few dB/cm), high erbium concentrations ( $\sim 1\times 10^{26}$ ion/m3) are required.

Redistribution of Erbium and Oxygen Recoil Atoms and the Structure of Silicon Thin Surface Layers Formed by High-Dose Argon Implantation through Er and SiO2 Surface Films

Using analytical high-resolution electron microscopy, the Si structure and the redistribution of Er and O recoil atoms embedded in thin (~10 nm) surface layers by Ar+ implantation with an energy of 250–290 keV and a dose of 1 × 1016 cm–2 through Er and SiO2 films, respectively, and subsequent annealing are studied. It is established that Si recrystallization fails at a distance of ~20 nm from the surface, where the erbium concentration of 5 × 1019 cm–3 critical for failure is achieved at T = 950°C. It disproves the generally accepted model of Er-atom transfer by the recrystallization front into SiO2 on the surface. Instead, it is shown that the redistribution of O recoil atoms to the initial oxide during annealing for immobile Er atoms provides the formation of surface-inhomogeneous erbium phases in such a way that the oxygen-enriched Er–Si–O phase turns out to be concentrated in the oxide, while the depleted Er–Si phase remains in Si. It explains the partial loss of implanted Er after removal of the oxide together with the Er–Si–O phase. It was shown that the formation of a high density of microtwins (locally up to 1013 cm–2) is associated with the formation of Ar bubbles and clusters, which is atypical for (100)–Si recrystallization.

Codoping Er‐N to Suppress Self‐Compensation Donors for Stable p‐Type Zinc Oxide

AbstractStable p‐type doping of zinc oxide (ZnO) is an unsolved but critical issue for ultraviolet optoelectronic applications despite extensive investigations. Here, an Er‐N codoping strategy for defect engineering of ZnO to suppress the self‐compensation of the donor‐type intrinsic point defects (IPDs) over the acceptor‐type ones is proposed. Via first‐principles calculations, the influence of nitrogen and erbium concentration on the stability of ZnO is investigated. The complex (ErZn‐mNO) consisting of multiple substitutional N on O sites and one substitutional Er on Zn site is a crucial stabilizer. With an increase of the concentration of N, the absorption edges redshift to lower energy due to the impurity band broadening in the bandgap. The results suggest that codoping Er‐N into the ZnO matrix is a feasible way to manufacture stable p‐type ZnO.

Er-Doped Nanostructured BaTiO₃ for NIR to Visible Upconversion.

Photoluminescent mechanisms in erbium-doped barium titanate nanoparticle systems were studied. Er3+ ions were introduced into the BaTiO3 lattice by the sol-gel method. The resulting Er3+ concentration was between 0% and 5%, with Ba/Ti ratios of 1.008 and 0.993. The stoichiometry of Ba and Ti concentrations in the lattice influenced the doping mechanism and placement of erbium ions in the lattice structure. Our research shows the existence of a strong correlation between Ba/Ti ratios, erbium concentration, phase structure and doping site location on the upconversion photoluminescence mechanisms. Competing upconversion emissions 2H11/2/4S3/2→4I15/2 at 523 and 548 nm respectively and other photoluminescent mechanisms as 4I9/2→4I11/2 around 4000 nm (2500 cm−1) were studied using Raman and emission spectroscopy. The upconversion process is predominant over other photoluminescent decay when the material presents high distortion in the surrounding activator.

Room temperature cathodoluminescence quenching of Er3+ in AlNOEr

This paper reports a cathodoluminescence (CL) spectroscopic study of nanogranular AlNOErx samples with erbium content, x, in the range 0.5–3.6 at%. A wide range of erbium concentration was studied with the aim of understanding the concentration quenching of CL. The composition of thin films, deposited by radiofrequency reactive magnetron sputtering, was accurately determined by Energy Dispersive X-ray Spectroscopy (EDS). CL emission was investigated in the extended visible spectral range from 350 nm to 850 nm. The critical concentration of luminescent activator Er3+ above which CL quenching occurs is 1%; the corresponding critical distance between Er3+ ions in AlNOErx is about 1.0 nm. The quenching mechanism is discussed. We discount an exchange-mediated interaction in favour of a multipole-multipole phonon-assisted interaction.

Erbium silicate compound optical waveguide amplifier and laser [Invited

In the process of information technology, as Moore's law becomes more and more close to the limit, the consensus to combine microelectronics and optoelectronics to develop silicon-based large-scale optoelectronic integration technology is inevitable. As the most important part of silicon photonic devices, a silicon-based light source still attracted great effort. In the traditional research, erbium-doped materials have played an important role in silicon-based light sources. Recent studies demonstrated that the erbium silicate compound had a high net gain attributable to a high erbium concentration that has no insolubility problem. This paper focuses on the theory, designs, simulations, preparation methods, process and device optimizations of the erbium silicate compound optical waveguide amplifier and laser. The erbium silicate compound materials with large optical gains can serve as potential candidates for future silicon-based scale-integrated light-source applications.

20 W splice-free erbium-doped all-fiber laser operating at 1610 nm.

We report on a splice-free erbium-doped all-fiber laser emitting over 20 W at a wavelength of 1610 nm, with a slope efficiency of 19.6 % and an overall efficiency of 18.3% with respect to the launched pump power at 976 nm. The simple cavity design takes advantage of fiber Bragg gratings written directly in the gain fiber through the polymer coating and clad-pumping from a single commercial pump diode to largely simplify the assembling process, making this cavity ideal for large-scale commercial deployment. Two single-mode and singly erbium-doped silica fibers were fabricated in-house: the first to assess the effects of a high erbium concentration (0.36 mol.% Er2O3), yielding a low efficiency of 2.5 % with respect to launched pump power, and the second to achieve the improved result mentioned above (0.03 mol.% Er2O3). Numerical simulations show the link between the performance of each cavity and ion pair-induced quenching.