Erbium Concentration Research Articles

High-gain erbium silicate waveguide amplifier and a low-threshold, high-efficiency laser.

Erbium-doped materials have played an important role in the fabrication of light sources used in silicon photonics. Recent studies demonstrated that erbium silicate nanowire had a high net gain attributable to its high erbium concentration and excellent material quality. We establish a more accurate and comprehensive theoretical model of erbium silicate nanowire, analyze the modeled nanowire's properties, and optimize a high-gain erbium silicate waveguide amplifier and low-threshold, high-efficiency laser by considering upconversion, energy transfer, and amplified spontaneous emission. The simulation results and previous experimental data reported in reference showed some agreement. A proposed waveguide amplifier, based on the optimized design, displayed a gain greater than 20 dB/mm. Then, a 3.3 mW low-threshold laser with a maximum power-conversion efficiency of 50% was modeled by choosing the optimized resonator cavity and reflector. The results indicate that erbium silicate compound materials with large optical gains can serve as potential candidates for inclusion in scale-integrated amplifiers and other applications requiring lasers.

Erbium doped sodium magnesium boro-tellurite glass: Stability and Judd-Ofelt analysis

Understanding the influence of rare earth ions in improving the optical properties of glasses are important in order to extend in advanced application. The behavior of series of Er3+ (1.0–2.0 mol %) doped B2O3-TeO2-MgO-Na2O glasses synthesized by conventional melt-quenching technique are explored. X-ray diffraction (XRD) pattern confirms the amorphous nature of the prepared glass sample. The DTA data asserts that the addition of Er3+ increased the thermal stability from 142 to 207 °C. The UV–VIS–NIR spectra reveal ten absorption bands centered at 4G11/2, 2H9/2, 4F5/2,4F7/2, 2H11/2, 4S3/2,4F9/2, 4I9/2, 4I11/2 and 4I13/2 from ground state of 4I15/2. The Judd–Ofelt Ω2 parameter values gradually decreases with the increase of erbium ions concentration from 0.5 to 2 mol %. From the Judd–Ofelt parameters (Ωt), transition probabilities (A), branching ratios (βR) of various transitions and their radiative lifetimes (τrad) are calculated. The up-conversion emission spectra of Er3+ exhibit four peaks centered at 538 nm, 554 nm, 653 nm and 822 nm assigned to 2H11/2 → 4I15/2, 4S3/2 → 4I15/2,4F9/2 → 4I15/2 and 4I9/2 → 4I15/2 transitions respectively in all samples. The maximum enhancement is evidenced at 1.5 mol% of Er2O3 by a factor of 3.11, 1.88 and 2.80 times for 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4I9/2 → 4I15/2 transitions respectively. A schematic energy level diagram is proposed. The effective band width at half maximum (FWHM) (Δλeff), stimulated emission cross-section (δPE) and the product of δPE×FWHM for 4S3/2 transitions of the glasses have also been studied and reported.

Modal properties of an Erbium-doped asymmetric single-mode slab waveguide in the glass-ceramics SnO2-SiO2 system

We investigate the modal properties (effective index and modal gain) of an active, Erbium-doped single-mode slab waveguide made of silica tin-dioxide glass-ceramics on Silica. Completed with a photo-inscribed Bragg grating, such a structure is a good candidate for realizing an optically pumped laser emitter. For total Erbium concentration of 9.84 × 10−4 mol/cm3 and a cross-section (for stimulated transitions) of σ ≈ 2 × 10−25 m2 in a discussed structure, the maximum achievable material gain in DFB with Quarter-Wave phase Shift (QWS-DFB) is σ Ntot ≈ 23 m−1. Taking into account the confinement factor, the maximum achievable modal gain, in complex amplitude, over the length of 10 mm is at about (αmaxL) ≈ 0.09.

Study of visible light emission under UV excitation in Y2O3:Er3+-Gd3+ and Y2O3:Eu3+-Gd3+ nanocrystals

In this work, we study the Y2O3:Er3+-Gd3+ and Y2O3:Eu3+-Gd3+ nanocrystals using statistical tools in order to quantify the effect of dopant concentration, crystallite size, induced strain, and lattice parameters on luminescent parameters such as intensity and color emission. Samples were synthesized using the sol–gel method. In the case of emission properties of Y2O3:Er3+-Gd3+, the most important factor is Erbium concentration, while the energy transfer between Gadolinium-Erbium is statistically insignificant, compared to the dynamics between Erbium–Erbium ions. On the other hand, the Y2O3:Eu3+-Gd3+ emission intensity depends on the dopant concentration: an increase of Gadolinium ions increases the emission intensity, and the quadratic effect of the Eu3+ ions reduce the emission intensity. However, the color coordinate is not so influenced by the dopant concentration; in the case of Y2O3:Er3+-Gd3+ samples, the color coordinate depends only on Er3+ concentration.

Optical, Physical and Structural Properties of Er3+ Doped Low‐Phonon Energy Vitreous Matrix: ZnO‐B2O3‐TeO2

This paper reports on the effect of varying concentration of erbium (Er3+) on the (70‐x/2) TeO2 − (20‐x/2) B2O3 −10 ZnO − x Er2O3 (where x = 0, 0.5, 1.0, 2.0, 2.5 mol.%) system, fabricated using the conventional melt quenching technique. The impact of Er3+ on the structural, physical, and optical properties of these zinc borotellurite glasses is investigated using Fourier transform infrared spectroscopy (FTIR), density measurements and UV–vis spectroscopy. The amorphous nature is confirmed using X‐Ray diffraction. FTIR results reveal that the glass is formed of fundamental borate and tellurite network units. The addition of Er2­O3 results in the formation of TeO3 at the expense of Te‐O‐Te linkage. The UV–vis spectroscopy results show that Er3+ enter the glass matrix showing absorption peaks corresponding to 4f‐4f transitions of trivalent Erbium ions (Er3+) from ground state 4I15/2 to the excited states 4F5/2, 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I9/2, 4I11/2, and 4I13/2. The optical band gap tends to decrease and refractive index increases with the increase in Er3+ concentration hence making these materials more efficient for the optical devices such as light emitting devices and image sensors.

On the interplay between Si-Er-O segregation and erbium silicate (Er2Si2O7) formation in Er-doped SiOx thin films

Er-doped silica or rich-silicon oxide has been widely studied as 1.54 μm emitters. The incorporation of Si-nanoclusters is known for improving luminescence yield of Er3+ ions through an efficient sensitization of the neighboring rare earth ions. The aim of this work is to investigate the influence of Silicon excess and Erbium concentration on the formation of silicon nanoclusters and Er-rich phase responsible of the quenching of 1.54 μm emission. Atom probe tomography and photoluminescence spectroscopy were used to explore the nanostructure and optical activity of Er-doped silicon rich silica. We present a direct evidence that both silicon excess and Er concentration influence the growth of Si nanoclusters, the formation of Er-Si-O phase and the luminescence of both Si nanoclusters and Er3+ ions. We explain these finding in relation with the growth mechanism of nanoparticles and the presence of a Snowman-like Janus morphology between silicon and Erbium silicates nanoparticles. In this contribution, we deciphered the nanoscale structure spatial correlations between Er and Si atoms in Er doped SiOX which remained unclear for a long time.

A Flat-Gain Double-Pass Amplifier with New Hafnia-Bismuth-Erbium Codoped Fiber

An efficient and compact double-pass optical fiber amplifier is demonstrated using a newly developed hafnia bismuth erbium co-doped fiber (HBEDF) as a gain medium. The HBEDF is fabricated using a modified chemical vapor deposition in conjunction with solution doping. The fiber has an erbium ion concentration of 12500 ppm. At the optimum length of 0.5 m, the HBEDF amplifier (HBEDFA) achieves a flat gain of 26 dB with a gain variation of less than 1.5 dB within a wavelength region from 1530 to 1560 nm when the input signal and pump power are fixed at −30 dBm and 140 mW, respectively. On the other hand, at the input signal power of −10 dBm, the HBEDFA also achieves a flat gain of 14.2 dB with a gain variation of less than 2.5 dB within a wide wavelength region from 1525 to 1570 nm. Compared with the conventional zirconia erbium co-doped fiber based amplifier, the proposed HBEDFA obtains a more efficient gain and lower noise figure. For an input signal of −30 dBm, the gain improvements of 6.2 dB and 4.8 dB are obtained at 1525 nm and 1540 nm, respectively.

Dielectric behavior of a lead-free electroceramics Ba1−xEr2x/3(Ti1−yZry)O3

Lead-free electroceramics samples of composition Ba1−xEr2x/3(Ti1−yZry)O3 (BETZ) with x = 0.01 and 0.02 and 0.20 ≤ y ≤ 0.35 have been elaborated by solid-state reaction technique. X-ray diffraction at room temperature discloses a single perovskite phase with a cubic symmetry. Dielectric measurements were carried out in the ranges (80–445 K) and (102–106 Hz) of temperature and frequencies respectively. The ceramics exhibited normal and/or relaxor ferroelectric properties then some of them have very interesting dielectric characteristics in the vicinity of room temperature. A wide dielectric anomaly combined to the dielectric maxima shift toward a higher temperature with increasing frequency denotes either a diffuse phase transition or relaxor behavior in some ceramics. For any erbium concentration, when titanium is substituted by zirconium, the temperature of the permittivity maximum TC (Tm) and the maximum permittivity (e′rmax) decreases while ΔTm(f)= [Tm(106 Hz) − Tm(102 Hz)] and tan δ increase. The diffuse phase transition parameters were calculated from the modified Curie–Weiss law linear fit. Further a relaxor nature was confirmed and endorsed by a good fit to the Vogel–Fulcher relation.

The effect of erbium oxide in physical and structural properties of zinc tellurite glass system

In this research, the melt-quenching method was used to synthesize a series of zinc tellurite glass systems doped with erbium oxide with the chemical composition of [(TeO2)0.7 (ZnO)0.3]1−x (Er2O3)x at different molar fraction, x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05. X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, density, molar volume, elastic and optical measurements were used to characterize the prepared glass samples. At room temperature, the result of the XRD, FTIR, density, elastic and optical properties were all recorded. An amorphous nature of glass samples is proven by the XRD spectra. The analysis of FTIR spectra shows the presence of functional vibration of tellurite network. It is observed that the density of the glass system increase with the molar fraction of Er2O3. The value of molar volume is found to be directly proportional to the density. Thus, the increment in the density value causes the increment of the molar volume due to the increase of erbium concentration. This in turn results in the creation of excess free volume due to the difference of atomic radius between erbium and tellurite. On the other hand, ultrasonic velocity was used to determine the elastic moduli of the glass systems. The elastic moduli such as longitudinal modulus, shear modulus, bulk modulus and Young's modulus give a fluctuating trend against the concentration of Er2O3. The increase of the elastic moduli is due to the mix former effect. In contrast, the decrease of the elastic moduli is due to the breakdown of Er2O3 in the zinc tellurite glass system which weakens the glass structure of the ternary tellurite system. The optical properties of the prepared glasses were determined by UV–vis analysis. The optical absorption was recorded at room temperature in the wavelength ranging from 220 nm to 800 nm. The optical absorption spectra reveal that fundamental absorption edge shifts to higher wavelength as the content of erbium oxide increase. The values of direct and indirect band gap have been calculated and are observed to decrease with the increase content of erbium oxide. However, the Urbach energy, refractive index, molar refraction and electronic polarizability are shown to be increased with an addition content of erbium oxides.

1532 nm sensitized luminescence and up-conversion in Yb,Er:YAG transparent ceramics

Luminescent properties of Yb,Er:YAG transparent ceramics containing 5 at% Yb3+ and 0.5, 1 and 1.5 at%, respectively, Er3+ ions have been studied. It has been found that increasing of erbium ions concentration increases both efficiency of nonradiative energy transfer Yb3+→Er3+ (which reaches 72% for 1.5 at% Er3+) and the luminescence in the range of 650–700 nm associated with 4F9/2, 11/2 → 4I15/2 transitions of Er3+ ions. It was also determined that the concentration quenching of sensitized luminescence of Er3+ ions at 1532 nm is associated with secondary excitation of metastable energy level of Er3+ followed by up-conversion emission.

High sensitization efficiency and energy transfer routes for population inversion at low pump intensity in Er organic complexes for IR amplification

Organic erbium complexes have long been of interest due to their potential for using the strong absorption into the organic to sensitise the erbium emission. Despite this interest there is remarkably little quantitative information on how effective the approach is and the discussion of the energy transfer mechanism is generally vague. Here we accurately quantify the sensitisation as a function of excitation pump density and model it using a rate equation approach. As a result, we can calculate the degree of population inversion for the erbium ions as a function of the pump intensity. We demonstrate that even when we increase the erbium concentration in the films from ~10 to ~80% we find a relatively small decrease in the sensitisation which we attribute to the large (>20 Å) Förster radius for the sensitisation process. We show that we can obtain population inversion in our films at very low pump powers ~600 mW/cm2. The calculated Förster radius for the organic erbium complexes suggests design rules for energy transfer between antennas and erbium ions in molecular systems and hybrid organic-inorganic nanoparticles.

Design, Synthesis, and Structure-Property Relationships of Er3+-Doped TiO₂ Luminescent Particles Synthesized by Sol-Gel.

Titania particles doped with various concentrations of Erbium were synthesized by the sol-gel method followed by different heat treatments. The shape and the grain growth of the particles were noticeably affected by the concentration of Erbium and the heat treatment conditions. An infrared emission at 1530 nm, as well as green and red up-conversion emissions at 550 and 670 nm, were observed under excitation at 976 nm from all of the synthesized particles. The emission spectra and lifetime values appeared to be strongly influenced by the presence of the different crystalline phases. This work presents important guidelines for the synthesis of functional Er3+-doped titania particles with controlled and tailored spectroscopic properties for photonic applications.

Erbium concentration anomaly as an indicator of nuclear activity: Focus on Natural waters in the Chernobyl exclusion zone

This study focused on measurement of lanthanides in surface water (SW) and ground water (GW) samples from the Chernobyl Exclusion Zone. Results showed that the total lanthanide concentration in SW ranges from 500 to 1100ngL−1 and is about 10 times lower than the GW concentration. The normalized patterns of lanthanide concentrations increase from lighter elements to heavier lanthanides. Concurrently, concentration anomalies of Ce, Eu, and Er are visible. The Er anomaly is the most noticeable and exceeds the theoretical calculation by about 13 times. The Ce and Eu anomalies are likely related to the variety of oxidation states of these elements. Meanwhile, the cause of the Er anomaly is not completely clear, but is likely related to the Chernobyl Nuclear Power Plant accident, since increased concentrations correlate with the distribution of contamination in the zone. 137Cs activity measurements partially confirm this hypothesis. Simultaneously, there is a relationship between the positive Er anomaly and increase in 235U concentrations. However, there is no reliable information in the literature that indicates that Er was used in the Chernobyl Nuclear Power Plant before the reactor accident.

Theoretical analysis of Er3+-doped telluride glass fiber amplifier for 2.700 μm laser amplification

The rate equations and power evolution equations of erbium-doped telluride glass fiber amplifier for both 1.530 and 2.700 μm lasers are solved numerically, the dependences of gain spectra on fiber length, dopant concentration and pump power are analyzed, and the gain of 2.700 μm laser is calculated and compared with the experimental result from reference. The numerical analysis shows that with 8 × 1024 ion/m3 erbium ion concentration, 5m fiber length and 600mW pump power, the gains at 1.530 and 2.700 μm may achieve 23dB or so. With larger power pump and higher dopant concentration, a net gain of 17 dB is obtained from the Er3+-doped telluride glass fiber amplifier for 110mW input signal. This fiber amplifier is promising for both 1.530 μm signal amplification and 2.700 μm laser amplification.

Effect of erbium ion concentration on structural and luminescence properties of lead borosilicate glasses for fiber amplifiers.

This investigation reports, the effect of the concentration of erbium and lead ions on the physical, structural and optical properties of lead borosilicate glasses. These glasses were synthesized by the melt quench method. In the synthesis, the concentration of the erbium (Er3+ ) ion was varied in the order of 0.0, 0.1, 0.5, 1.0 and 2.0mol% and lead (Pb2+ ) ion was varied in the order of 30, 29.9, 29.5, 29 and 28mol%. The glasses were analyzed using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and UV-vis-NIR spectroscopy. From XRD, the amorphous nature of lead borosilicate glasses was confirmed. The functional groups which were present in the glasses have been identified by analyzing the FT-IR spectrum. From the absorption spectra, the oscillator strengths as well as the Judd-Ofelt (JO) intensity parameters were determined and compared with other hosts. The JO intensity parameters were further used to calculate certain radiative properties for the excited luminescent levels of Er3+ ion. From emission spectra, full width at half maxima (FWHM), stimulated emission cross-sections (σe ) and certain lasing parameters were evaluated and compared with reference host glasses. The lifetimes of 4 I13/2 excited level of Er3+ ion have also been recorded and analyzed. The calculated and experimental lifetimes were compared in terms of quantum efficiencies. From the photoluminescence analysis, the erbium doped lead borosilicate glasses well suited for optical fiber amplifiers are discussed.

Effect of erbium concentration on spectroscopic properties of Er: CaLaGa3O7 crystals with 2.7 μm emission

The synthesis and optical characterizations of CaLaGa3O7 crystals with different Er dopant concentration are reported. The optical parameters related to absorption and emission cross-sections were evaluated and compared. It was found that the NIR fluorescence weakens, at the same time Mid-IR fluorescence intensity strengthens with the increment of Er3+ ion dopant concentration in Er: CaLaGa3O7 crystals. Furthermore, the energy transfer mechanism in Er: CaLaGa3O7 crystal was studied in this work. Besides, the radiative transfer microscopic parameters of 4I11/2 and 4I13/2 levels were theoretically analyzed. Hence, these results indicate that 30 at% Er3+ doped CaLaGa3O7 crystal has potential applications in 2.7 μm laser.

Giant optical gain in a single-crystal erbium chloride silicate nanowire

Rare-earth optical materials with large optical gain are of great importance for a wide variety of applications in photonics and quantum information due to their long carrier lifetimes and quantum coherence times, especially in the realization of efficient lasers and amplifiers. Until now, such materials have achieved a gain of less than a few dB cm–1, rendering them unsuitable for applications in nanophotonic integrated circuits. Here, we report the results of the signal enhancement and transmission experiments on a single-crystal erbium chloride silicate nanowire. Our experiments demonstrate that a net material gain over 100 dB cm–1 at wavelengths around 1,530 nm is possible due to the nanowire's single-crystalline material quality and its high erbium concentration. Our results establish that such rare-earth-compound nanowires are a potentially important class of nanomaterials for a variety of applications including, for example, subwavelength-scale optical amplifiers and lasers for integrated nanophotonics, and quantum information. Erbium chloride silicate nanowire promises optical gain for nanophotonic circuits.

THERMOLUMINESCENCE PROPERTIES OF ERBIUM DOPED SrSO4

SrSO4 (strontium sulphate) has been prepared by the chemical precipitation technique and characterized by XRD and TEM (Transmission Electron Microscopy). TEM shown the formation of compound in ring like structure with average particle size 45 nm. The erbium (Er) doped to SrSO4 by different concentrations for the sake of improving the TL-sensitivity of SrSO4, were found the optimum concentration of erbium is (22wt%). SrSO4:Er (0.22wt%) has five glow peaks at (116.5 ˚C – 183 ˚C – 344 ˚C – 412 ˚C – 431 ˚C). High gamma doses as TL-sensitization method have been used. By these means the TL-intensity of treated samples proved about 30 times enhancement, which make it very promising detector and dosimeter suitable for ionizing radiation.

Erbium diffusion in titanium dioxide

The diffusivity of erbium in the anatase phase of titanium dioxide (TiO2) has been studied for various temperatures ranging from 800 °C to 1, 000 °C. Samples of TiO2, with a 10 nm thick buried layer containing 0.5 at% erbium, were fabricated by radio-frequency magnetron sputtering and subsequently heat treated. The erbium concentration profiles were measured by secondary ion mass spectrometry, allowing for determination of the temperature-dependent diffusion coefficients. These were found to follow an Arrhenius law with an activation energy of (2.1±0.2) eV. X-ray diffraction revealed that the TiO2 films consisted of polycrystalline grains of size ≈ 100 nm.

Direct Evidence for Coupled Surface and Concentration Quenching Dynamics in Lanthanide-Doped Nanocrystals

Luminescence quenching at high dopant concentrations generally limits the dopant concentration to less than 1-5 mol% in lanthanide-doped materials, and this remains a major obstacle in designing materials with enhanced efficiency/brightness. In this work, we provide direct evidence that the major quenching process at high dopant concentrations is the energy migration to the surface (i.e., surface quenching) as opposed to the common misconception of cross-relaxation between dopant ions. We show that after an inert epitaxial shell growth, erbium (Er3+) concentrations as high as 100 mol% in NaY(Er)F4/NaLuF4 core/shell nanocrystals enhance the emission intensity of both upconversion and downshifted luminescence across different excitation wavelengths (980, 800, and 658 nm), with negligible concentration quenching effects. Our results highlight the strong coupling of concentration and surface quenching effects in colloidal lanthanide-doped nanocrystals, and that inert epitaxial shell growth can overcome concentration quenching. These fundamental insights into the photophysical processes in heavily doped nanocrystals will give rise to enhanced properties not previously thought possible with compositions optimized in bulk.