Doped Fluorophosphate Glasses Research Articles

Broadband near infrared emission of Er3+ ions doped fluorophosphate glasses for solid state laser applications

A series of glass compositions (P2O5 + Bi2O3 + Na2CO3 + SrF2 + xEr2O3) with different concentrations of erbium ions (Er3+) was synthesized using the melt quenching method and the samples were subjected to thorough characterization to explore their optical and structural properties. In order to ascertain the amorphous nature of the glass and acquire a deeper understanding of its chemical bonding, conventional methods of characterization, such as X-ray diffraction and Fourier transform infrared spectroscopy, were utilized. The Judd-Ofelt intensity parameters were computed using the absorption spectra of glasses doped with Er3+, providing vital information about the local environment and coordination of Er3+ ions in the glass matrix. Using the Judd-Ofelt intensity parameters and emission spectra to calculate the radiative parameters like total radiative transition probability (AT), radiative lifetime (τR) and radiative branching ratios for 4I13/2 → 4I15/2 transition. The McCumber theory is used to study absorption and emission cross-section for 4I13/2 → 4I15/2 transition. Prepared the PBNSEr05 glass sample suitable candidates for 1.53 μm solid state laser applications.

Optical ridge waveguides in Nd3+‐doped fluorophosphate glasses fabricated by carbon ion implantation and femtosecond laser ablation

AbstractIn this work, the ridge waveguide was formed by the femtosecond laser ablation with a central wavelength of 0.808 μm and a speed of 50 μm/s on the planar Nd3+‐doped fluorophosphate glass waveguide that was fabricated by the C3+ ion implantation with an energy of 6.0 MeV and a fluence of 1.0×1012 C3+s/mm2. The mechanism of the ion‐implanted waveguide was discussed by the Stopping and Range of Ions in Matter 2013. The cross‐section morphology of the ridge waveguide was captured by an optical microscope. Its mode characteristics were analyzed by the end‐face coupling method. The ridge Nd3+‐doped fluorophosphate glass waveguides have potential as fundamental structures for many optoelectronic devices including waveguide amplifiers and lasers.

Study on the luminescence properties of the Eu3+ and Tb3+ dual-doped fluorophosphate glasses for UV sensitization detection

In this article, NaPO3-BaF2-AlF3-CaF2 glasses doped with Eu3+ and Tb3+ were manufactured by conventional melt-quenching method, and they showed good physical properties throughout various measurements: density, refractive index, Raman scattering, and X-ray diffraction (XRD). Basing on Judd-Ofelt theory, the Ω2/4/6 values were calculated. The higher Ω2 values of the Eu3+-doped fluorophosphate glasses indicate a highly polarized environment around Eu3+ ions. Accompanying with the Eu3+ and Tb3+ dual-doped glass, it showed that the response of excitation absorption extended by whole UVA region. This phenomenon was explained by the energy transferring between Eu3+ and Tb3+. Combining the dual-doped glass with silicon-based photodetectors, the spectral response of the detectors in the UVA region was improved up to 20%.

Study of controlling phase separation in Yb3+-doped fluorophosphate glasses via molecular dynamics simulations

Yb3+-doped fluorophosphate (FP) glasses are considered to be important laser glass materials with wide application prospects. However, fluorine phase separation greatly affects the lasing properties of the materials. Besides, understanding the phase separation mechanism of FP glass and finding practical methods to control it remain unsolved problems. Herein, we study the phase separation of Yb3+-doped FP glass with the compositions of P2O5-Al2O3CaF2-YbF3 based on molecular dynamics simulations. The results reveal immiscible behaviors that the glass separates into fluoride-rich phase and aluminophosphate-rich residual matrix. The Al3+ coordinated with both O2− and F− form the [Al(O,F)n] polyhedrons on oxide-fluoride interface. Furthermore, to understand the structure of Al3+ dependent glass phase, we generate a series of FP glasses by replacing Ca2+ with Al3+. Those models indicate that [Al(O,F)n] polyhedron plays an important role in breaking the connection of fluoride-rich regions, preventing the further growth of fluoride phase and stabilizing the double-phase structure effectually.

Spectroscopic properties and Stark splitting of Nd3+ ions in different host glasses to obtain pure blue laser

In this study, we investigated the spectroscopic properties and Stark splitting of Nd3+ in several typical host glasses by focusing on the 0.9 μm fluorescence (4F3/2 → 4I9/2). Absorption, emission spectra and decay curves of Nd3+ doped borate, phosphate, fluoride, tellurite, silicate, germanate and fluorophosphate glasses were measured. Judd−Ofelt parameters, Stark splitting and crystal field strength in these glasses were calculated and analyzed. Results demonstrated that broad absorption and emission bands, large Judd−Ofelt parameters (5.14 × 10−20 cm2), strong local field strength (7089.2 cm−1) and high values of fluorescence branching ratio (43.7%) and fluorescence lifetime (542.95 μs) of Nd3+ ions were found in silicate glass. Results indicate that silicate and germanate host glasses show promising potential for pure blue lasers by frequency doubling of 0.9 μm fluorescence.

Spectroscopic properties of Yb3+-doped fluorophosphate glasses with low phosphate content

A series of new fluorophosphate glasses of 5Ba(PO3)2–10BaF2–18.5CaF2–10MgF2–18.5SrF2–(38–x)AlF3–xYbF3 (x = 0.5, 1, 2, 5, 8, 10) composition was synthesized. Experimental characterization, including absorption, luminescence, and luminescence kinetics measurements, was performed. Based on experimental data, the optimal concentration of Yb3+ ions, providing the highest gain, was established. To characterize potential laser performance of the studied glasses several parameters, including pump saturation, minimal pump intensity, and minimal fraction of excited ions needed to balance gain and absorption, were calculated. Dependence of gain cross section on the excited state population was determined to characterize amplifying properties of the glasses.

Synthesis and luminescence characteristics of Tb3+-doped fluorophosphate glass for UV detection

In this study, Tb3+-doped NaPO3-BaF2-AlF3CaF2 glasses were prepared using a traditional melt-quenching method. The physical properties of host glass were systematically studied. The host glass exhibits good mechanical properties. The glass forming criterion of 117 °C testifies its good capacity to be softened and shaped. High transparency supports a strong absorption in the range of 340–390 nm. The Judd–Ofelt parameters were calculated based on the measured spectral absorption. Ω2 value above 8 × 10−20 cm2 indicates a highly polarized environment around Tb3+, which is beneficial to its fluorescence. No concentration quenching was observed in Tb4O7 concentration range of 0–1.5 mol%. A fluorescence-assisted experiment verifies that the Tb3+-doped glass can provide 12% responsivity enhanced at peak for the detection of a silicon-based probe in the UV region.

Improvement of Gamma Radiation Shielding Features for Fluorophosphate Glasses Doping with Sm2O3 (PZBKNA)

This research reported on the radiation safety characteristics of doped fluorophosphate glasses with heavy rare earth lanthanide (Sm2O3) in the composition 40P2O5/30ZnO/20BaF2/3.8K2TeO3/1.2Al2O3/5.0Nb2O5/30000 ppm Sm2O3 and 40P2O5/30ZnO/20BaF2/3.8K2TeO3/1.2Al2O3/5.0Nb2O5/40000 ppm Sm2O3 in mol%. The parameters for shielding like that mass attenuation coefficient, MAC, linear attenuation coefficient, LAC, tenth value layers, TVL, half-value layers, HVL, effective atomic number, (Zeff), mean free path, MFP, electron density, Neff, electronic cross-sections, ECS, and total atomic cross-sections, ACS, were calculated between 0.015 and 15 MB of preparation glasses. The protection parameters of the current glasses are good in comparison to industrial materials used for nuclear shieldings, such as glass RS 253, ordinary concrete (OC), hematite serpenite (HS), or basalt magnet (BM). From the above mention results, the prepared glasses can be used as radiation safety materials.

Effect of the phosphate content on the spectroscopic and lasing properties of Er3+/Yb3+-doped fluorophosphate glasses

The influence of phosphate content on the formation and luminescent properties of Er3+/Yb3+-doped fluorophosphate glass has been studied. Using the Judd-Ofelt theory the phenomenological intensity parameters Ωt (t = 2; 4; 6) were obtained. The change of Judd-Ofelt parameters indicates minor differences in Er3+environment with increase in the phosphates content up to 10 mol.%. It was shown that in the studied fluorophosphates glasses erbium ions remain in the fluoride environment. The increase in phosphate content leads to lifetime change of erbium laser level from 9.4 ms to 7.8 ms. Using the Judd-Ofelt intensity parameters Ωt the stimulated emission cross-section of the 4I13/2→4I15/2 transition has been calculated. The gain shape of the glasses with lower (2–10 mol. %) phosphate content has been found to be smoother than for phosphate glasses with 20 mol.% Ba(PO3)2, which makes former very attractive gain material.

Tuning multicolor emission in AgNCs/Tm3+/Mn2+-doped fluorophosphate glasses

Herein we report the synthesis of highly-doped silver nanocluster in fluorophosphate glasses through the melting-quenching method in order to achieve sensitization with Tm3+ and Mn2+ ions. Blue and red emission belonging to Tm3+ (470 to 490 nm) and Mn2+ (550 to 750 nm) ions could be obtained via non-resonant excitation of Tm3+ and Mn2+. Slight decrease of the fluorescence decay times confirmed an energy transfer as a possible mechanism to explain the Tm3+ and Mn2+ emission. The composition of 5 mol% of AgNO3, 0.4 mol% of Tm2O3 and 0.2 mol% of MnF2 in our sample leads to distance between donor (silver nanoclusters) and acceptor (Tm3+-Mn2+) as short as 11 Å, which suggests that the main mechanism for blue and red emission from Tm3+ and Mn2+ is Förster Resonance Energy Transfer (FRET). The results presented here show that the studied material has potential application for multicolor generation as luminophore in white light emitting diodes (W-LED).

Optical and spectroscopic properties of Ho3+-doped fluorophosphate glasses for visible lighting applications

Holmium (Ho3+)-doped fluorophosphate glasses (P2O5–BaF2–CaF2–TiO2–Ho2O3, PCfBfTiH) were fabricated by melt-quenching technique. The glass transition (548 °C) and crystallization (577 °C) temperatures and glass stability factor (161 °C) were obtained from DSC analysis. Judd-Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6) of PCfBfTiH15 glass were evaluated. Intense green (545 nm) emission was obtained for the 5S2 + 5F4 → 5I8 transition upon excitation of 451 nm. The stimulated emission cross-section (σem) of PCfBfTiH15 glass was found to be as high as 2.01 × 10−20 cm2. Decay curves of the 5S2 + 5F4 → 5I8 transition were analyzed by double exponential function. High lifetime of 11.29 μs for the 5S2 + 5F4 level was obtained. The CIE chromaticity coordinates for the emission spectra were professed that the green emission owing to the 5S2 + 5F4 → 5I8 transition may be useful for laser and display applications at around 545 nm.

Structural, spectroscopic and optical gain of Nd3+ doped fluorophosphate glasses for solid state laser application

Nd3+ doped fluorophosphate glasses (PANCaFN) with chemical composition of (50-x) P2O5–12Na2O–8Al2O3–10CaO–10KF–10CaF2-xNd2O3 (where x = 0, 0.5, 1.0, 1.5 and 2.0 mol%) have been successfully prepared by melt-quenching method and characterized by several techniques. The optical absorption measurements exhibited signature of Nd3+ absorption bands in fluorophosphate glasses showed. The spectroscopic analysis have been carried out using Judd-Ofelt parameters and oscillator strength to determine radiative properties such as radiative transition probability (AR), branching ratio (βr), lifetime (τ), emission cross-section (σe) and quantum efficiency (η). The highest emission intensity was found at 1060 nm for transition 4F3/2 → 4I13/2 under excitation wavelength of 582 nm for PANCaFN2. The emission cross section, branching ratio and lifetime were evaluated and showed 4.92 × 10−20 cm2, 0.7 and 200 μs, respectively. More importantly, the outstanding quantum efficiency of PANCaFN2 could reach to 98.92%. The addition of Nd3+ ion into fluorophosphate glass could enhance the spectroscopic properties which could play as a potential candidate for solid state applications. Theoretical optical gain evaluation and experimental calculation confirmed that PANCaFN2 had the higher gain than other samples.

High emission cross-section Er3+-doped fluorophosphate glasses for active device application

The fluorophosphate (FP) glasses modified with different concentrations of Mg(PO3)2 and ErF3, were synthesized by simple melt-quenching technique. The effect of Mg(PO3)2 addition on structural and spectroscopic properties of the Er3+-doped FP glasses were explored. The glass stability factor was determined from thermal analysis that showed that the prepared glasses possessed greater stability above >100 °C. The Raman analysis was carried out in order to know the vibrational groups in the fabricated glasses. In order to study the local structure and covalency between Er3+ ions and ligand environment, the Judd-Ofelt parameters were derived by Judd-Ofelt theory from the absorption spectra of Er3+-doped FP glasses. The emission spectra showed an intense and broadband at 1532 nm originating from 4I13/2→4I15/2 transition of Er3+ ion upon 980 nm diode laser excitation. The larger emission cross-section of 2.15 × 10−20 cm2 and an extensive lifetime of 12.50 ms, respectively, were noticed for 3 mol% ErF3 and 40 mol% Mg(PO3)2 based FP glass. Considering those results, studied Er3+-doped FP glasses have a feasibility to be used as active media for solid-state lasers and optical amplifiers at 1532 nm.

Spectroscopic and lasing properties of Er3+/Yb3+-doped fluorophosphate glass with small additives of phosphates

The influence of lead fluoride on the formation and luminescent properties of glass and glass-ceramics has been studied. Using the Judd-Ofelt theory, the intensity parameters Ωt have been obtained. The stimulated emission cross-section of the 4I13/2→4I15/2 transition has been determined. The energy transfer from ytterbium to erbium with 96% efficiency was found with an erbium laser level lifetime of ∼8 ms. The gain shape of the glass under study has been found to be smoother than for phosphate glasses, which makes the former very attractive gain material for ultra-short laser sources. For the first time, fluorophosphate glass-ceramics were obtained with nanocrystals doped with erbium and ytterbium ions.

Eu3+ doped high-brightness fluorophosphate laser-driven glass phosphors

High-brightness orangish red fluorescence emissions were captured in Eu3+ doped fluorophosphate (NBFP) glasses with outstanding rare earth (RE) ion solubility under laser excitation. Highly efficient emissions of Eu3+ doped NBFP glasses in the wavelength range of 580−720 nm make the phosphors potential candidates as a remarkable orangish red lighting source. The net emission power and the net emission photon number in 6.0wt% Eu2O3 doped NBFP glass were derived to be 6.48 mW and 2.08 × 1016 cps under the excitation of 465 nm laser with 53.46 mW optical power, respectively, and total measured quantum yield was as high as 54.03%. When the excitation power was increased to 561 mW, the luminous flux of 6.0wt% Eu2O3 doped NBFP glass was up to 31.21 lm, demonstrating that Eu3+ heavy-doped NBFP glasses are potential lighting source materials. Thus, the laser-driven high-brightness phosphors originating from the sufficient photon release of Eu3+ ions promote further development of orangish red lighting source.

Effect of Ba(PO3)2 addition on the optical properties of Tm3+-doped fluorophosphate glasses

Tm3+-doped fluorophosphate glasses with varying Ba(PO3)2 content were prepared by the melt quenching technique and their thermal and optical properties were investigated by studying differential scanning calorimetry, Raman spectra, fluorescence spectra, decay curves, transmission and absorption spectra. The Judd-Ofelt theory was applied to calculate the intensity parameters of the resultant glass. The glass forming criterion was obtained to be 146 °C. The gain coefficient and fluorescence lifetime of Tm3+-doped fluorophosphate glass with 20 mol% Ba(PO3)2 were 3.045 × 10−21 cm2 × ms and 0.406 ms, respectively, which are the highest value among the fluorophosphate glasses with similar components to the best of our knowledge. These results clearly indicate that the prepared fluorophosphate glass is an attractive candidate for 2 μm lasers and as a gain media for optical amplifier applications.

Luminescence and energy transfer studies of Ce3+/Dy3+ doped fluorophosphate glasses

The fluorophosphate (PKABfNf:P2O5+K2O+Al2O3+BaF2+NaF2) glasses doped with single and co-doped (Ce and/or Dy) were prepared by conventional melt quenching technique and characterized their luminescence properties. The emission spectra of co-doped glass (PKABfNfCeDy) showed a broad blue band of Ce3+ ions combined with the sharp peaks of Dy3+ ions. Judd-Ofelt (JO) intensity parameters have been obtained from the optical absorption spectra of 1.0 mol% of Dy3+ (PKABfNfDy1.0) glass. JO theory has been used to find the radiative properties of PKABfNfDy1.0 glass by using Futchbauer-Ladenbergh formula. The (Ce3+/Dy3+) co-doped glass exhibit radiative energy transfer (ET) from Ce3+ to Dy3+ upon UV excitation and then intensity is increased with increase in Dy3+ ion concentration. The ET mechanism from Ce3+ to Dy3+ ion has been analyzed. The theoretical ET efficiency and quantum yield values were calculated from the emission spectrum of the Ce3+ and (Ce3+/Dy3+) co-doped glasses. These results suggest that the co-doped PKABfNfCeDy glasses are promising candidate for commercial white light applications.

Efficient 2 μm emission and energy transfer mechanism of Ho3+ doped fluorophosphate glass sensitized by Er3+ ions

Fluorophosphate glass co-doped with Er3+ and Ho3+ ions has been synthesized by high temperature melting method. Using a commercially available 980 nm laser diode, intense about 2 μm emissions were successfully obtained in present Ho3+/Er3+ co-doped glasses without obvious quenching. To understand 2 μm fluorescence behaviors of the prepared glasses, 1.55 μm emission spectra, energy transfer mechanism and microparameters from different levels of Er3+ to Ho3+ ions have been obtained and discussed. As a result, the Er3+/Ho3+ co-doped fluorophosphate glass with excellent spectroscopic properties might be appropriate host material for 2 μm solid laser.

Photoluminescence, optical and structural properties of Pr3+-doped fluorophosphate glasses and their induced defects by gamma irradiation

Multicomponent fluorophosphate host glass and samples containing Pr2O3 as dopant oxide with added (0.25, 0.5, 1.0 or 2 wt%) were prepared by melting and annealing technique. Multiple characterization techniques were employed to investigate optical, photoluminescence and FTIR spectral properties of the prepared glasses before and after being gamma irradiated with doses of 2, 9 Mrad. Optical absorption spectra reveal only distinct UV absorption in the undoped glass which is related to trace iron impurities while the Pr2O3-doped samples exhibit two series of characteristic extended peaks within the visible and near-IR regions which are due to absorption of Pr3+ ions. Gamma irradiation causes a continuous increase of the intensity of the UV absorption with irradiation. The Pr2O3-doped samples reveal obvious effects including the shift of the absorption to longer wavelength only of the first visible series of absorption peaks while the second series of peaks in the near IR region remain almost unchanged. These optical changes upon irradiation are suggested to be related to photochemical reactions with the liberated pairs of electrons and positive holes during the irradiation process. Photoluminescence (PL) measurements indicate the appearance of five emission peaks and three excited peaks before irradiation and their intensities increase with the Pr2O3 content. With irradiation, the PL spectra reveal limited changes with 2 Mrad but with 9 Mrad, the first emission peaks show few variations but the main high intense peak at 600 nm remains unchanged but the intensities of the peaks become very close with the increase of Pr2O3 content. The PL results support the stability of the Pr3+ ions as evidenced by the persistence of the optical absorption spectra. FTIR spectra of the studied glasses reveal the appearance of repetitive vibrational bands due to main building PO4 units mainly with Q2 and Q3 units with some suggested fluorophosphates groups (PO3F)− AlF4 (AlFO) groups. Gamma irradiation decreases the intensities of some bands together with the generation of a distinct band at 1455 cm−1. The FTIR results indicate the maintenance of the vibratonal bands after irradiation and the changes in the intensity of some bands are related to suggested variations in the bond angles and/or bond lengths of structural phosphate groups.

Structural and optical investigations on Eu3+ doped fluorophosphate glass and nano glass-ceramics

Eu3+ doped transparent glass and glass-ceramic were prepared by melt quenching method of P2O5-CaF2-Eu2O3 composition. The glass-ceramic samples were obtained by heat treatment of initial glass at 640 °C for 4 h. The structure properties of samples were characterized by XRD, DTA, SEM and EDS and their optical and spectroscopic studies were done using optical absorption, reflectance, FTIR, and emission spectra. X-ray diffraction patterns evidenced the formation of major phase of Ca(PO3)2 nano crystals along with minor phases of Al2(SiF6)3, Eu and Eu5(PO4)3F. The Tauc plots shows that the heat treatment increases allowed direct band gap and Urbach energy. Up frequency conversion properties of glassy and glass-ceramic samples have been investigated. Upconversion phenomena were observed in Eu3+ doped glass-ceramics samples.