Showing papers on "Erbium published in 2020"

Judd–Ofelt analysis and physical properties of erbium modified cadmium lithium gadolinium silicate glasses

Abstract: Erbium doped 50SiO2 -30Li2O- 1Gd2O3- (19 − x) CdO and x Er2O3 glass system, where (0 ≤ x ≥ 2.5), mol%, has been prepared by the conventional melt quenching technique. The physical, structural and optical properties are explained by analyzing the data obtained from X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV–Visible (UV–Vis-NIR) and photoluminescence results. X-ray powder diffraction patterns show broad peaks which conform glassy nature of the sample. FTIR spectroscopy reveals the presence of SiO4, CdO4 and Er–O vibration groups in the glass samples. The optical absorption spectra in the wavelength range of 200–2500 nm were measured and the optical band gaps, Urbach energy, Electronegativity (χ) Electron Polarizability (α°), and Optical basicity (˄) were determined. The optical absorption spectra of Er3+ ions in these glasses show eleven bands and are assigned to the transitions from ground state to excited levels. It was found that the optical band gap increases from 3.19 to 3.51 eV with the increase in Er2O3 concentration. The strong sharp peak belongs to Er+3 emission is investigated in photoluminescence spectra at ordinary condition (1 atm. and at room temperature). It excites by wavelength of 385 nm and gives pale green color at 559 nm. Judd–Ofelt theory has been used to analyze the spectra arising from erbium ions doped 50 SiO2 -30 Li2O- 1Gd2O3- (19 − x) CdO and x Er2O3. The intensity parameters Ω2,4,6 of the present complex and lifetimes of selected levels are theoretically calculated as well.

Erbium complexes as pioneers for implementing linear light-upconversion in molecules

Abstract: Since the non-linear optical (NLO) response of matter to incident excitation light does not require long-lived intermediate excited states working as relays, the conversion of low-energy photons into high energy light beams using second-harmonic generation (second-order NLO process) or two-photon absorption (third-order NLO process) can be implemented either in low-phonon macroscopic solids or in molecules containing high-energy vibrations. However, harnessing the very weak non-linear absorption coefficients requires (very) intense excitation sources, typically lasers, for getting reasonable emitted intensities. In contrast, the piling of successive near-infrared photons to get visible emission using linear optics, i.e. upconversion, is much more efficient, but it depends on the existence of intermediate excited states possessing long residence lifetimes. Therefore, upconversion usually occurs in low-phonon ionic solids or nanoparticles doped with pertinent activators. The recent recognition that trivalent erbium coordination complexes possessing high-frequency oscillators may act as dual visible/near-infrared activators, which implies the existence of at least one long-lived intermediate excited state in these complexes, paved the way for the implementation of the first upconversion processes within isolated molecules. Beyond a justification for using trivalent lanthanides, and especially erbium, for the manipulation of the energy of photons in molecules using linear optics, this tutorial review summarizes the current level of developments in the field of molecular-based upconversion and discusses some forthcoming challenges.

Experimental observation of coherent interaction between laser and erbium ions ensemble doped in fiber at sub 10 mK

Abstract: Rare-earth ions doped in solid-state materials are considered promising candidates for quantum information applications, especially for photonic quantum memory. Among them, erbium ions doped in an optical fiber have attracted a lot of attentions due to their ability to provide efficient photon-atom interaction on a telecom-C band compatible transition. The coherent photon-atom interaction, which is crucial for quantum memory, has not yet been investigated for erbium ions doped in fiber at the temperature of sub 10 mKlinebreak with the magnetic environment. In this paper, we experimentally observe optical nutation, which results from the coherent interaction between laser and erbium ions ensemble, in a piece of 9.5-m-long fiber with the erbium concentration of 200 ppm. We also extract the transition dipole moment from the results of optical nutation and further investigate its dependence on laser wavelength and magnetic field. A transition dipole moment of (3.424$\\pm$0.019)$\\times$10$^{-32}$ C$\\cdot$m is obtained at the wavelength of 1537 nm and magnetic field of 0.2 T. Our results could pave the way for realizing solid-state quantum networks at telecom-C band.

Erbium dopants in silicon nanophotonic waveguides

Abstract: The combination of established nanofabrication with attractive material properties makes silicon a promising material for quantum technologies, where implanted dopants serve as qubits with high density and excellent coherence even at elevated temperatures. In order to connect and control these qubits, interfacing them with light in nanophotonic waveguides offers unique promise. Here, we present resonant spectroscopy of implanted erbium dopants in such waveguides. We overcome the requirement of high doping and above-bandgap excitation that limited earlier studies. We thus observe erbium incorporation at well-defined lattice sites with a thousandfold reduced inhomogeneous broadening of about 1 GHz and a spectral diffusion linewidth down to 45 MHz. Our study thus introduces a novel materials platform for the implementation of on-chip quantum memories, microwave-to-optical conversion, and distributed quantum information processing, with the unique feature of operation in the main wavelength band of fiber-optic communication.

Erbium oxide and Cerium oxide-doped borosilicate glasses as radiation shielding material

Abstract: In this paper, the radiation shielding parameters such as linear attenuation coefficients (LAC, µ), mass attenuation coefficients (MAC, µ/ρ), effective atomic numbers (Zeff), effective electron den...

Laser Sources Based on Rare-Earth Ion Doped Tellurite Glass Fibers and Microspheres

Abstract: In recent years, huge progress has been made in the development of rare-earth ion doped tellurite glass laser sources, ranging from watt- and multiwatt-level fiber lasers to nanowatt level microsphere lasers. Significant success has been achieved in extending the spectral range of tellurite fiber lasers generating at wavelengths beyond 2 μm as well as in theoretical understanding. This review is aimed at discussing the state of the art of neodymium-, erbium-, thulium-, and holmium-doped tellurite glass fiber and microsphere lasers.

Synthesis and Characterization of a Novel Erbium Doped Poly(vinyl alcohol) Films for Multifunctional Optical Materials

Abstract: Polymer films based on poly vinyl alcohol (PVA) doped with different contents (0, 4, 8, 16, 20 and 28) wt% of Erbium(III) ions were synthesized by the simple solution casting technique. The structural characteristics of the films were studied by X-ray diffraction pattern (XRD), Fourier transform infrared (FT-IR) spectroscopy and atomic force microscopy measurements (AFM) measurement whereas the optical behavior of these films have been investigated using UV–Vis-NIR spectroscopy and photoluminescence measurements. The structural parameters of the interplanar (d) spacing, crystallite length (L) and the average interchain separation determined from the XRD and the absorption bands of the active IR groups recorded in FT-IR spectra indicate bonding of positively charged Er3+ ions with negatively charged OH groups of the PVA chains. The average cluster size (D) of the samples estimated from AFM data shows larger values than that obtained from XRD measurements. The optical gaps obtained from absorption spectra fitting and Tauch relations are approximately equal and slightly decreased by Er3+ ions incorporation in the PVA matrix whereas the high frequency refractive indices estimated according to Moss and Dimitrov formulae showing small increase. Three intense peaks of 607 nm, 733 nm and 783 nm wavelengths due to energy levels transitions of erbium were recorded in the photoluminescence spectra PVA–Er3+. The collected data support consideration of PVA–Er3+ films as a promising optical polymer material in microptics, planar polymer waveguides, polymer optical fiber and polymer light emitting diodes applications.

2D molybdenum carbide (Mo2C)/fluorine mica (FM) saturable absorber for passively mode-locked erbium-doped all-fiber laser

Abstract: Abstract As a new member of saturable absorber (SA), molybdenum carbide (Mo2C) has some excellent optical properties. Herein, we report a new type of Mo2C/fluorine mica (FM) SA device. Uniform and compact Mo2C films were deposited on the FM by magnetron sputtering method. In order to increase the laser damage threshold, an additional protective layer of silicon oxide was deposited on the Mo2C. The FM is a single-layer structure of 20 μm, and its high elasticity makes it not easy to fracture. The transmission rate of FM is as high as 90% at near infrared wavelength. FM has better heat dissipation and softening temperature than organic composite materials, so it can withstand higher laser power without being damaged. In this work, Mo2C/FM SA was cut into small pieces and inserted into erbium-doped fiber laser to achieve mode-locked operation. The pulse duration and average output power of the laser pulses were 313 fs and 64.74 mW, respectively. In addition, a 12th-order sub-picosecond harmonic mode-locking was generated. The maximum repetition rate was 321.6 MHz and the shortest pulse duration was 338 fs. The experimental results show that Mo2C/FM SA is a broadband nonlinear optical mode-locker with excellent performance.

Design of a Multi-Wavelength Fiber Laser Based on Tm:Er:Yb:Ho Co-Doped Germanate Glass

Abstract: In this article, for the first time, an efficient multi-wavelength fiber laser based on a Tm:Er:Yb:Ho co-doped germanate glass, optically pumped at 980 nm wavelength and simultaneously emitting at 1550 nm, 1800 nm and 2050 nm wavelengths, is designed and optimized. An exhaustive model, taking into account the energy transfer phenomena between different rare earths, is developed. The device behavior is investigated by means of several parametric sweeps with respect to the input pump power, the fiber length, the dopant concentrations and the output mirrors reflectivities. Four optimal concentrations have been found by means of a home-made computer code based on particle swarm optimization (PSO) approach, allowing a global solution search. These concentrations allow levels of output powers very close to each other, equal to 20 mW $\pm$ 0.1 $\%$ at 1550 nm, 1800 nm and 2050 nm, respectively. These results predict the possibility of tailoring the dopant concentrations in order to construct broadband optical sources with similar emission powers at multiple wavelengths and broadband amplifiers.

Isolating Nanocrystals with an Individual Erbium Emitter: A Route to a Stable Single-Photon Source at 1550 nm Wavelength.

Abstract: Single-photon emitters based on individual atoms or individual atomic-like defects are highly sought-after components for future quantum technologies. A key challenge in this field is how to isolate just one such emitter; the best approaches still have an active emitter yield of only 50% so that deterministic integration of single active emitters is not yet possible. Here, we demonstrate the ability to isolate individual erbium emitters embedded in 20 nm nanocrystals of NaYF4 using plasmonic aperture optical tweezers. The optical tweezers capture the nanocrystal, whereas the plasmonic aperture enhances the emission of the Er and allows the measurement of discrete emission rate values corresponding to different numbers of erbium ions. Three separate synthesis runs show near-Poissonian distribution in the discrete levels of emission yield that correspond to the expected ion concentrations, indicating that the yield of active emitters is approximately 80%. Fortunately, the trap allows for selecting the nanocrystals with only a single emitter, and so this gives a route to isolating and integrating single emitters in a deterministic way. This demonstration is a promising step toward single-photon quantum information technologies that utilize single ions in a solid-state medium, particularly because Er emits in the low-loss fiber-optic 1550 nm telecom band.

Er3+,Yb3+-doped oxyfluorotellurite glasses—Impact of temperature on spectroscopic properties and optical sensor qualities

Abstract: Oxyfluorotellurite glasses co-doped with erbium (0.5%) and ytterbium (2%, 5%) were manufactured from high purity reagents at 840 °C in air. Differential thermal analysis was used to estimate the temperatures of glass transition and glass crystallization of 2% and 5%Yb co-doped glasses. The effect of Yb3+ co-doping on relaxation dynamics of erbium excited states was demonstrated by the means of excitation, emission and fluorescence lifetime spectroscopy. Up-conversion luminescence spectra were studied in a function of temperature in the 295–675 K range, yielding information on thermal quenching of the emission and a temperature sensing model based on 2H11/2–4I15/2 to 4S3/2–4I15/2 erbium fluorescence intensity ratio. Application potential of the investigated material in optical sensor thermometry was evaluated. Maximum absolute and relative sensitivities were established at 6.45 × 10−3 K−1 at T = 675 K and 0.46 %K−1 at T = 400 K, respectively.

Studies of the morphology and optical properties of nano erbium oxide embedded in PMMA matrix

Abstract: Doping polymethyl methacrylate (PMMA) with nano earth metal-oxides can play a significant role for modern optical devices. Films of PMMA doped with nEr2O3 (PMMA/nEr2O3, 4 and 8 wt%) were prepared using the casting technique. The size distribution of nEr2O3 was investigated at the nanoscale level by using high-resolution transmission electron microscopy (HR-TEM), and was found to be mixture of spherical particles ranging from 44 to 48 nm. The structure of the PMMA/nEr2O3 films was investigated using Fourier infrared transmission specrtoscopy, FITR. The linear and calculated nonlinear optical properties absorption were also investigated. The optical band gap of our fabricated films decreased by 6% due to doping by nEr2O3 at 8 wt%. Moreover, the estimation of the spectral moments (M−1 and M−3), energy dispersion, static refractive index (n0), the third-order susceptibility (χ(3)), nonlinear refractive index (n2) and the infinite dielectric constant (Ɛ∞) indicated a significant enhancement with increasing the concentration of nEr2O3. The present results indicated that PMMA/nEr2O3 could be used in different nonlinear optical applications such as image sensing and light-emitting diodes.

Reduced Graphene Oxide-Silver Nanoparticles for Optical Pulse Generation in Ytterbium- and Erbium-Doped Fiber Lasers

Abstract: This work has demonstrated the potential of a reduced graphene oxide silver/polyvinyl alcohol (rGO-Ag/PVA) film as a saturable absorber (SA) in ytterbium and erbium based Q-switched optical fiber lasers. The facile hydrothermal method was used to synthesize the nanocomposite between rGO and Ag nanoparticles. This was followed by a simple solution method to form the rGO-Ag film using PVA as the host polymer. From nonlinear absorption characterization, the rGO-Ag/PVA SA was determined to have a modulation depth of 30%, a nonsaturable loss of 70%, and a saturable intensity of 0.63 kW/cm2. Stable self-starting Q-switched pulses were obtained at the threshold pump power of 72.76 mW and 18.63 mW in the ytterbium-doped (YDFL) and erbium-doped fiber laser (EDFL) cavities respectively. The center operating wavelengths were observed at 1044.4 nm and 1560 nm for the two cavities. The shortest pulse width and maximum repetition rate of the YDFL and EDFL were 1.10 µs and 62.10 kHz and 1.38 µs and 76.63 kHz respectively. This work has demonstrated that the rGO-Ag/PVA film is suitable as an SA for pulse generation in the 1.0 and 1.5 μm regions and would have many potential photonics applications.

150 km φ-OTDR sensor based on erbium and Raman amplifiers

Abstract: Extending the sensing range for monitoring the railways, pipelines, borders, long structures, etc., has great importance in distributed fiber optic sensors development. Phase-sensitive optical time-domain reflectometry (φ-OTDR) sensors are the best candidate for this purpose. Optical fiber amplifiers in φ-OTDR sensors have increased the sensing range. A φ-OTDR sensor using combination of Erbium and Raman amplifiers has been demonstrated with a sensing range of 128 km. In this paper, we presented a disturbance monitoring up to 150 km utilizing Erbium and bi-directional Raman amplifications. In the proposed sensor, disturbances at 30, 70 and 120 km distances are applied and Rayleigh backscattered signals are investigated.

Erbium emission in Er:Y2O3 decorated fractal arrays of silicon nanowires.

Abstract: Disordered materials with new optical properties are capturing the interest of the scientific community due to the observation of innovative phenomena. We present the realization of novel optical materials obtained by fractal arrays of silicon nanowires (NWs) synthesized at low cost, without mask or lithography processes and decorated with Er:Y2O3, one of the most promising material for the integration of erbium in photonics. The investigated structural properties of the fractal Er:Y2O3/NWs demonstrate that the fractal morphology can be tuned as a function of the sputtering deposition angle (from 5° to 15°) of the Er:Y2O3 layer. We demonstrate that by this novel approach, it is possible to simply change the Er emission intensity by controlling the fractal morphology. Indeed, we achieved the increment of Er emission at 560 nm, opening new perspectives on the control and enhancement of the optical response of novel disordered materials.

Phase segregation induced third order nonlinear saturable absorption behavior in Erbium doped ZnO nanoparticles synthesized by facile hydrothermal method

Abstract: Here in this work, we present the dominance of rare earth dopant (Er) in association with the surfactant (Oleylamine) on the structural, surface morphology, optical, and nonlinear optical properties of hydrothermally grown ZnO nanoparticles. The polycrystalline nature of the prepared nanostructures is confirmed by the XRD diffractograms. The formation of erbium related compound (erbium oxide) in the highest Er doped ZnO nanoparticles is visible from the XRD diffractogram. The incorporation of Er at different doping concentrations (1 at. wt.%, 3 at. wt.%, and 5 at. wt.%) brings noticeable morphological changes in the FESEM images. The Raman spectra reveal the retention of wurtzite structure in undoped and Er doped nanoparticles. The disappearance of A1 (TO) mode in ZnEr3 and ZnEr5 nanoparticles shows the deteriorated polar lattice bond strength. The phase segregation observed from XRD spectrum of ZnEr5 nanoparticles is further confirmed by the detection of local vibrational mode (LVM). A severe decrement in the bandgap of the Er doped nanoparticles is noticed from UV–Vis spectroscopy. A continuous fall in the intensity in the NBE emission with increasing Er doping concentration is attributed to the formation of surface defects below the conduction band edge. The nonlinear optical parameters of the nanoparticles are quantified with the assistance of open aperture and closed aperture Z-scan curves. A remarkable switching from reverse saturable absorption (RSA) to saturable absorption (SA) and self-defocusing to self-focusing mechanisms in ZnEr5 shed light on the impact of phase segregation on the nonlinear response of the Er doped nanoparticles. The quantified values of nonlinear parameters look promising in the fabrication of photonic devices.

A six-octave optical frequency comb from a scalable few-cycle erbium fiber laser

Abstract: A compact and robust coherent laser light source that provides spectral coverage from the ultraviolet to infrared is desirable for numerous applications, including heterodyne super resolution imaging[1], broadband infrared microscopy[2], protein structure determination[3], and standoff atmospheric trace-gas detection[4]. Addressing these demanding measurement problems, laser frequency combs[5] combine user-defined spectral resolution with sub-femtosecond timing and waveform control to enable new modalities of high-resolution, high-speed, and broadband spectroscopy[6-9]. In this Letter we introduce a scalable source of near-single-cycle, 0.56 MW pulses generated from robust and low-noise erbium fiber (Er:fiber) technology, and we use it to generate a frequency comb that spans six octaves from the ultraviolet (350 nm) to mid-infrared (22500 nm). The high peak power allows us to exploit the second-order nonlinearities in infrared-transparent, nonlinear crystals (LiNbO$_3$, GaSe, and CSP) to provide a robust source of phase-stable infrared ultra-short pulses with simultaneous spectral brightness exceeding that of an infrared synchrotron[10]. Additional cascaded second-order nonlinearities in LiNbO$_3$ lead to comb generation with four octaves of simultaneous coverage (0.350 to 5.6 $\mu$m). With a comb-tooth linewidth of 10 kHz at 193 THz, we realize a notable spectral resolving power exceeding 10$^{10}$ across 0.86 PHz of bandwidth. We anticipate that this compact and accessible technology will open new opportunities for multi-band precision spectroscopy, coherent microscopy, ultra-high sensitivity nanoscopy, astronomical spectroscopy, and precision carrier-envelope phase (CEP) stable strong field phenomena.

Controlling light emission by engineering atomic geometries in silicon photonics.

Abstract: By engineering atomic geometries composed of nearly 1000 atomic segments embedded in micro-resonators, we observe Bragg resonances induced by the atomic lattice at the telecommunication wavelength. The geometrical arrangement of erbium atoms into a lattice inside a silicon nitride (SiN) microring resonator reduces the scattering loss at a wavelength commensurate with the lattice. We confirm dependency of light emission to the atomic positions and lattice spacing and also observe Fano interference between resonant modes in the system.

Enhancement of lifetime in Er-doped silica optical fiber by doping Yb ions via atomic layer deposition

Abstract: In this study, the influence of ytterbium ions (Yb3+) on the fluorescence lifetime of erbium (Er)-doped silica optical fiber (EDF) is investigated. An Er/Yb co-doped fiber is fabricated by modified chemical vapor deposition (MCVD), along with the atomic layer deposition (ALD) method. Moreover, the spectral properties of this fiber, such as absorption, luminescence, excitation and emission spectra, and the fluorescence lifetime, are studied experimentally; the results of the experiments are then compared with those of the EDF. The results revealed the existence of a broadband luminescence spectrum at 800-1300 nm. The fluorescence lifetime of the Er/Yb co-doped fiber at 1531 nm is 11.77 ms, whereas that of the EDF is 10.16 ms. The lifetime of Yb3+ is 415 µs, which is 565 µs less than that of the Yb-doped fiber (980 µs), at 1033 nm. Simultaneously, various models of the Er-doped, Yb-doped, and Er/Yb co-doped fibers in three membered ring (3MR) structures were built, and their excited states were analyzed. The results indicated that an energy transfer is associated with the change in lifetime, and that the doping of Yb3+ significantly improves the fluorescence lifetime of Er3+ at 1533 nm.

Erbium-Doped Nanoparticle–Polymer Composite Thin Films for Photonic Applications: Structural and Optical Properties

Abstract: Erbium-doped nanocrystal (NC)-dispersed polymer thin films are attractive core materials for use in optical waveguides as they can provide high optical gain and enable the formation of compact wave...

Erbium doped Bi2O3-B2O3 glass-ceramics containing Bi3B5O12 and CaF2 nanocrystallites for 1.53 μm fiber lasers

Abstract: Trivalent erbium ions doped Bi2O3-B2O3 transparent glass ceramics containing CaF2 were prepared and characterized through X -ray diffraction, scanning electron microscopy, Fourier transform infrared absorption, optical absorption, and near infrared emission for 1.53 μm fiber lasers. The glass ceramics obtained by applying thermal treatment at 575 °C for 5 h and 575 °C for 10 h contain Bi3B5O12 and CaF2 crystallites. The Judd-Ofelt theory was applied to evaluate various spectroscopic and laser characteristic properties. The NIR emission corresponding to the 4I13/2 → 4I15/2 (∼1.53 μm) transition was studied by exciting the samples at 514.5 nm laser radiation. The stimulated emission cross-sections of ∼1.53 μm luminescence were also obtained applying the Mc Cumber theory. The experimental results confirm that the transparent glass ceramic obtained at a thermal treatment of 575 °C for 10 h is more suitable to design fiber lasers for diverse applications in the fields of industry, medicine and scientific research.