Lithium Fluoroborate Glasses Research Articles

Dysprosium ion concentration variations and their comprehensive influence on the physical, structural and optical properties of multi-component borate glasses for luminescence tailoring

A set of Zinc Strontium Lithium Fluoroborate (ZSLFB) glasses with different concentrations of Dysprosium ions (Dy3+) was created using the melt quench technique. The presence of non-crystallinity and various functional groups have been confirmed via X-Ray Diffraction (XRD) and Infrared Fourier Transform FT-IR measurements, respectively. The band gap values obtained from Tauc plot were utilised to analyse the optical characteristics. The photoluminescence (PL) emission spectra display three well-defined intensity peaks at wavelengths of 481, 574, and 664 nm. The intensity of peaks exhibits an ascending trend until a concentration of 0.5 mol% of Dy3+ ions is reached, after which it decreases. The PL intensity maintains up to 82 % at 200° C to room temperature, showing excellent thermal stability. The Judd Ofelt (J-O) parameter values pursue the Ω2 > Ω6 > Ω4 pattern, which shows its asymptotic nature. The CIE coordinates were assessed and determined to fall inside the white region. The interaction in the non-radiative energy transfer process was elucidated by utilizing the Dexter theory and Inokuti-Hiryama (I-H) model.

Influence of Pr3+ ions on structural, photoluminescence, dielectric, and mechanical properties of barium lithium fluoroborate glasses

The influence of Praseodymium Oxide (Pr6O11) on the physical, optical parameters, photoluminescence, dielectric, and mechanical properties for 20BaF2 + 10Li2O+(70-x) B2O3 + xPr6O11 (where x = 0.0, 0.5, 1.0, 1.5 and 2.0 mol %)] glasses was investigated. FTIR spectra of the borate glass network doped with Pr6O11 demonstrate the vibrational modes. The current study found that adding Pr3+ ions to the glass increased the glass density, packing density (VP), oxygen packing density (OPD), and rare earth ion concentration (N). The optical parameters include refractive index molar refraction and molar polarizability, optical transmission, and reflection loss. All the optical parameters increased except optical transmission decreased with the rising of Pr3+ ions in the glass. The photoluminescence emission intensity increased with the concentration of Pr3+ ions. The dielectric constant decreased while AC conductivity increased with the applied frequency, particularly in the high-frequency region. The elastic moduli, including longitudinal, shear, bulk, Young, and microhardness increased with increasing the content of Pr3+ ions in the glass.

Structural, optical, and magnetic studies on novel Pr- doped barium lithium fluoroborate glass system

The current study involves the spectral analysis of barium lithium fluoroborate glasses doped with Praseodymium Oxide (Pr6O11). The glass composition used in the study is (70-x) B2O3+20BaF2+10Li2O+xPr6O11 (where x = 0.0, 0.5, 1.0, 1.5 and 2.0 mole%) and was prepared using the traditional melt quenching technique. The amorphous nature of the prepared glasses was confirmed by the X-ray diffraction spectrum. The Raman spectroscopy demonstrated that the addition of Pr6O11 to the barium lithium fluoroborate glasses caused structural changes. The thermal analysis confirmed that Pr6O11 doping increases glass transition temperature and enhances glass thermal stability. The optical characteristics of the glasses that were prepared were analyzed through the use of UV, Vis, and NIR absorption. The calculation of the optical bandgap for both direct and indirect allowed transitions was conducted in order to gain insight into the electronic band structure, as well as to determine the Urbach energy values. The investigation includes an analysis of the refractive index and extinction coefficient across the whole range of wavelengths. The magnetic behavior of all samples was observed to be soft ferromagnetic. The glass material's ability to provide windows for optical fiber at a wavelength of 1550 nm suggests its potential as a viable source for waveguide lasers and its appropriateness for use in applications involving optical fiber amplification.

Photoluminescence Properties of Ho3+-doped Fluoroborate Optical Glasses

A trivalent rare earth ion Holmium doped zinc magnesium lithium fluoroborate (ZMLB) glasses with the composition of 10ZnO-10MgO-20LiF-(60-x)B2O3-xHo2O3 (where x = 0, 0.1, 0.3, 0.5 and 1 mol%) were prepared by a well-known melt quenching procedure. The produced glass samples structural, optical, emission and decay curve characteristics have been investigated. From the X-ray diffraction investigation, it is confirmed all the produced glasses possess amorphous nature. The borate-oxygen and vibration bonds were noticed by using Fourier transform infrared analysis. From the ultraviolet-visible absorption studies, the produced glasses absorption peaks were noticed and optical energy band gap values also identified by using Tauc’s relation. Under excitation with 456 nm, the Ho3+ activated ZMLB glasses luminescence spectra consist of three luminescence bands positioned at 550, 677 and 764 nm were corresponding electronic transitions are 5S2 + 5F4 → 5I8, 5F5→ 5I8 and 5F4→ 5I7, respectively. From all these emission bands the prominent emission band observed at 550 nm (green). For the Ho3+ activated ZMLB glasses, the lifetimes were decreased with the enhance of Ho3+ doping content owing to energy transfer in resonance form in between Ho3+ ions. From emission spectra, the CCT and CIE coordinates were estimated, and the CIE values are pointed greenish-yellow area in CIE image. Therefore, all these findings convey that the current zinc magnesium lithium fluoroborate glasses conceivably significant candidate for green display and lighting applications.

Gamma-ray interactions with ytterbium ions doped BLFB glasses for shielding applications

The ytterbium (Yb3+) ions doped barium lithium fluoroborate (BLFB) glasses have been prepared with conventional melt quenching method and explored for nuclear radiation (γ-ray) shielding applications. The XRD analysis confirms the aperiodic nature of the glasses. The glass density was increased from 2.84 to 4.87 (gm/cm3) with the increase of Yb3+ content. The refractive index (n) increased from 1.544 to 1.599 while the molar volume (Vm) decreased from 27.656 to 17.458 (gm/cm−3) for 0.05YbBLFB to 2YbBLFB glasses. The optical packing density (OPD) increased from 9.943 to 15.751 (mol/cm3) while the electronic polarizability (αe) varied from 346.23 to 5.913 (10–22 cm3) for all glasses due to the increase of Yb3+ ions’ concentration. By employing the Phy-X/PSD program, γ-ray attenuation parameters such as linear attenuation coefficient (μ), mass attenuation coefficient (μ/ρ), effective atomic number (Zeff), effective electron density (Neff), half value layer (HVL), tenth value layer (TVL), and mean free path (MFP) were evaluated within the γ-ray energy range of 15 KeV–15 MeV. In addition, the geometric progression (G‒P) fitting method is used to investigate the exposure and energy absorption buildup factors (EBF and EABF) with discrete penetration depths (1–40 mfp) of all glasses. Also, the fast neutron removal cross-section (FNRCS) parameter is also estimated for all glasses. Therefore, among all the glasses, 2YbBLFB glass possesses higher μ/ρ, Zeff, Neff, Zeq values and lower HVL, TVL, and MFP values. And this glass is suggested for the best gamma-ray shielding applications.

Optical and luminescence characteristics of europium doped barium lithium fluoroborate glasses

This is a report on the synthesis and spectroscopic study of europium doped barium lithium fluoroborate glasses (Eu3+:BLFB) by conventional melt quenching technique and their structural and luminescence characteristics. The X-Ray diffraction result confirms the amorphous nature of the glasses. The Judd-Ofelt parameters (Ω2, Ω4, Ω6) were calculated from the emission spectra and the trends in the intensity parameters are found to be Ω2 > Ω4 > Ω6. The JO parameters were used to predict the radiative properties like transition probability, branching ratio, radiative lifetime and stimulated emission cross section for all the emission levels of europium (Eu3+) ions. Phonon energy (1228 cm−1) have been calculated from the phonon side band spectra. From the emission spectra, fluorescence intensity ratio (R), color chromaticity values were calculated and x, y parameters which indicates the emission of red color, as observed in the in the CIE diagram. The nature of decay profiles of 5D0 state of Eu3+ in all glasses were measured and were compared with the calculated lifetimes.

Concentration-dependence and luminescence studies of erbium doped barium lithium fluoroborate glasses

The present spectral investigations on erbium doped barium lithium fluoroborate glasses of the composition (70-x) H3BO3 − 10 Li2CO3 − 10 BaCO3 − 5 CaF2 − 5 ZnO − x Er2O3 (where x = 0.05, 0.1, 0.5, 1, 2 in wt %) were prepared by the conventional melt quenching technique. Dielectric constant, refractive index, electronic susceptibility, reflection loss and interionic distance were calculated for all the glass samples. The X-ray diffraction spectrum confirmed the amorphous nature of the prepared glasses. The optical properties of the prepared glasses were investigated by UV–Vis-NIR absorption and emission spectra. Nephelauxetic ratio and bonding parameters were determined from the absorption spectra and are found to be covalent in nature. Optical bandgap corresponding to the direct and indirect allowed transition were calculated to understand the electronic band structure and the Urbach energy values. Judd-Ofelt (JO) intensity parameters (Ωλ = 2, 4 and 6) were determined from the absorption spectrum. These JO parameters were used to analyse the transition probability (A), branching ratio (βR), and the stimulated emission cross section (σPE) parameter for different emission intensities. The emission of infrared at 1550 nm indicates that the glass material can act as a promising wave guide laser source and is suitable in optical fiber amplifier applications.

Effect of Eu3+ ions on optical and fluorescence studies of Nd3+ ions doped zinc-lithium fluoroborate glasses

Nd3+ single and Nd3+/Eu3+ co-doped ZnF2-LiF-Na2CO3-Bi2O3-H3BO3, zinc lithium fluoroborate (ZLFNBiB) glasses with good optical properties have been prepared by high temperature melt-quenching method. The single and co-doped samples exhibiting emission bands centered at 874, 1058 and 1330 nm under the excitation of 808 nm laser diode (LD). The photoluminescence spectra for co-doped glasses were recorded under the 394 and 464 nm of xenon lamp as excitation sources. The Judd-Ofelt intensity parameters were calculated from optical absorption spectrum and radiative parameters from the emission spectrum of 0.5 mol% of Nd3+ doped glass. The large stimulated emission cross-section and branching ratio values are evaluated and compared with the other Nd3+ doped systems, the energy transfer from Eu3+ to Nd3+ ions is observed and thoroughly discussed from NIR emission spectra (λexc = 394 nm) of co-doped glasses. The decay profiles are recorded for all the concentrations of co-doped samples and the experimental lifetimes (τexp) were obtained from the decay profiles. The binding energy and Urbach energy values of prepared glass samples were calculated and discussed.

Optical properties of Nd3+ doped barium lithium fluoroborate glasses for near-infrared (NIR) emission

The neodymium doped barium lithium fluoroborate (Nd3+: BLFB) glasses with the chemical composition (70-x) H3BO3 - 10 Li2CO3 - 10 BaCO3- 5 CaF2-5 ZnO - x Nd2O3 (where x = 0.05, 0.1, 0.25, 0.5, 1, 2 in wt %) have been prepared by the conventional melt quenching technique and characterised through optical absorption, near infrared emission and decay-time measurements. The x-ray diffraction studies confirm the amorphous nature of the prepared glasses. The optical absorption spectra and emission spectra were recorded in the wavelength ranges of 190–1100 nm. The optical band gap (Eg) and Urbach energy (ΔE) values were calculated from the absorption spectra. The Judd-Ofelt intensity parameters were determined from the systematic analysis of the absorption spectrum of neodymium ions in the prepared glasses. The emission spectra exhibited three prominent peaks at 874, 1057, 1331 nm corresponding to the 4F3/2 → 4I9/2, 11/2, 13/2 transitions levels respectively in the near infrared region. The emission intensity of the 4F3/2 → 4I11/2 transition increases with the increase in neodymium concentration up to 0.5 wt% and the concentration quenching mechanism was observed for 1 wt% and 2 wt% concentrations. The lifetime of the 4F3/2 level was found to decrease with increasing Nd3+ ion concentration. The nature of energy transfer process was a single exponential curve which was studied for all the glasses and analysed.

Optical character enrichment of NdF3 – doped lithium fluoroborate glasses

Optical spectra in combination with Fourier transform infrared FTIR spectra of base undoped lithium fluoroborate glasses and samples that doped with NdF3 were measured before and after subjecting to (8Mrad) gamma irradiation. Base glass reveals strong absorption in the UV region attributed to unavoidable iron impurity (Fe3+ ions) while gamma irradiated sample shows extended additional peaks related to the photochemical reactions of some Fe2+ impurities transformed to Fe3+ ions by acquiescent positive holes while the induced visible band is related to (BOHC) boron oxygen hole center or (NBOHC) nonbridging oxygen hole center. The NdF3-doped samples display the same strong UV spectra as the undoped sample beside additional characteristic visible absorption peaks due to the presence of Nd3+ ions. UV–Vis. absorption spectra were applied to assess their optical properties, comprising indirect and direct optical energy band gaps taking into account the effect of gamma irradiation. Infrared absorption spectra of the undoped lithium fluoroborate glass reveal characteristic IR bands due to both BO3 and BO4 borate groups as usually observed in various alkali–oxide B2O3 glasses. Suggested BO3F tetrahedral units are advanced to interpret the close similarity of the IR spectra obtained from fluoroborate glass with alkali or alkaline earth oxide borate glasses. The increase of NdF3 content causes minor changes in the IR spectra that can be attributed to the non-conventional loose OH, H2O or similar vibrations while the structural building borate units remain unchanged as evidence from the deconvoluted FTIR data before and after the irradiation process.

Optical properties and spectroscopic study of different modifier based Pr3 +:LiFB glasses as optical amplifiers

In this paper, we report the preparation and optical characterization of Pr3+ doped lithium fluoro borate (LiFB) glasses for six different chemical compositions of Li2B4O7-BaF2-NaF-MO (where M=Mg, Ca, Cd and Pb), Li2B4O7-BaF2-NaF-MgO-CaO and Li2B4O7-BaF2-NaF-CdO-PbO. The structural and optical properties of these glasses were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), optical absorption and photoluminescence techniques. The optical absorption spectra of Pr3+ ions in LiFB glasses have been recorded in the UV–VIS-NIR region. The optical absorption data are used to calculate various spectroscopic parameters such as Racah (E1, E2, E3) and spin-orbit interaction (ξ4f) parameters. Judd-Ofelt (J-O) (Ωλ where λ=2, 4 and 6) intensity parameters were determined by applying J-O theory, which in turn used to calculate the radiative properties such as radiative transition probabilities (A), radiative lifetimes (τR), integrated absorption cross-sections (Σ) and branching ratios (βr) for all emission levels of Pr3+ ion in different LiFB glass matrices. By using the J-O theory and luminescence parameters, stimulated emission cross sections (σp) of prominent transitions, 3P0→3H4 and 1D2→3H4 of Pr3+ ion in all LiFB glasses were calculated. 3P0→3H4 possesses higher branching ratios and stimulated emission cross-sections for the Pr3+:LiFB(Mg-Ca) glass, which can be used as a best laser excitation. The optical gain parameter (σpxτR) was noticed higher in Pr3+:LiFB(Mg-Ca) and Pr3+:LiFB(Cd-Pb) glasses for the transition 3P0→3H4 transition, and these glasses have potential for optical amplification at 488 nm wavelength.

Optical and μ-FTIR mapping: A new approach for structural evaluation of V2O5-lithium fluoroborate glasses

Collective optical and FTIR spectral measurements were carried out for undoped and V2O5 doped lithium fluoroborate glasses before and after gamma irradiation (8Mrad). The undoped glass shows strong UV absorption which is related to the presence of unavoidable trace iron (Fe3+ ions) present as unavoidable impurities. The V2O5-containing glasses reveal additional UV-near visible bands due to the presence of vanadium ions mainly in the pentavalent state with some contribution of trivalent vanadium ions. The studied glasses show marked resistance to gamma irradiation, revealing the maintenance of the optical spectral curves without variations. FTIR spectra reveal vibrational bands due to borate groups in triangular and tetrahedral coordination by the sharing of suggested (BO3F−) tetrahedral units through the modification effect of LiF on B2O3. The suggested tetrahedral units show similar vibrational modes in their wavenumbers to (BO4) units formed by alkali oxide.A new micro-FTIR mapping in combination with ordinary FTIR was also studied for further insight of the distribution of vibrational modes and structural arrangements within the studied glasses.

Influence of CuO content on the structure of lithium fluoroborate glasses: Spectral and gamma irradiation studies

Glasses of lithium fluoroborate of the composition LiF 15%–B2O3 85% with increasing CuO as added dopant were prepared and characterized by combined optical and FTIR spectroscopy before and after gamma irradiation. The optical spectrum of the undoped glass reveals strong UV absorption with two distinct peaks at about 235 and 310nm and with no visible bands. This strong UV absorption is related to the presence of unavoidable trace iron impurity (Fe3+) within the materials used for the preparation of this glass. After irradiation, the spectrum of the undoped glass shows a decrease of the intensity of the UV bands together with the resolution of an induced visible broad band centered at about 520nm. The CuO doped glasses reveal the same UV absorption beside a very broad visible band centered at 780nm and this band shows extension and splitting to several component peaks with higher CuO contents. Upon gamma irradiation, the spectra of all CuO-doped glasses reveal pronounced decrease of their intensities. The response of irradiation on the studied glasses is correlated with suggested photochemical reactions together with some shielding effect of the copper ions. The observed visible band is related to the presence of copper as distorted octahedral Cu2+ ions.Infrared absorption spectra of the prepared glasses show repetitive characteristic triangular and tetrahedral borate units similar to that published from alkali or alkaline earth oxides B2O3 glasses. A suggested formation of (BO3/2F) tetrahedral units is advanced through action of LiF on B2O3 and these suggested units showing the same position and number as BO4 tetrahedra.

Spectroscopic analysis of Ho3+ transitions in different modifier oxide based lithium–fluoro-borate glasses

In recent investigations it was observed that the presence of different structural groups in borate glasses was favorable for spectroscopic investigations of rare earth doped borate glasses. Consequent to these observations, the heavy metal fluoride glasses doped with Ho3+ ions received much attention due to their wide transparency in the ultraviolet to infrared region. Keeping these observations in view, the present paper makes an attempt to present spectral investigations of Ho3+ doped lithium–fluoro-borate glasses of the compositions Li2B4O7–BaF2–NaF–MO (where M=Mg, Ca, Cd and Pb), Li2B4O7–BaF2–NaF–MgO–CaO and Li2B4O7–BaF2–NaF–CdO–PbO. These rare earth doped glasses were synthesized by melt quenching technique and an investigation was carried out to observe the structural (SEM and FT-IR) and optical (absorption and luminescence) properties. The paper also aims at the determination of three phenomenological Judd–Ofelt intensity parameters and special attention was paid to study the emission properties by employing the J–O intensity parameters. The visible emission spectra of Ho3+ ion in different lithium–fluoro-borate glasses were recorded by exciting the samples at 409nm. The results revealed that among all the glass matrices, cadmium glass matrix have shown higher stimulated emission cross-section, which indicates that this is a good lasing material at this wavelength and highly useful for laser excitation.

Structural and optical properties of Nd3+ in lithium fluoro-borate glass with relevant modifier oxides

Modifier oxides (MgO, CaO, CdO and PbO) based Nd3+ doped lithium fluoro-borate glasses were prepared by using the conventional melt quenching technique. The structural and optical properties of all lithium fluoro-borate glasses were characterized by means of X-ray diffraction and SEM analysis (structural), optical absorption, near infrared luminescence and lifetime decay measurements(optical). Broad XRD spectra and smooth surface of SEM image analysis reveals that these glasses have amorphous nature. Judd–Ofelt intensity parameters were calculated and used to explain the structural properties and to determine the radiative properties (radiative transition probabilities, branching ratios and radiative lifetimes) of efficient meta stable states. By pumping with diode laser excitation source at 805nm, a broader NIR emission transition, 4F3/2→4I11/2 was observed. This transition possesses large stimulated emission cross-section (σp) and branching ratio (β) values. These values are compared with another Nd3+ doped glass. The decay from the 4F3|2 level is found to be bi-exponential. The 4F3/2 level gives the highest quantum efficiency for all Nd3+ doped lithium fluoro-borate glasses. It indicates the efficient laser emission at 1.06μm.

Structural, thermal and optical investigations of Dy3+ ions doped lead containing lithium fluoroborate glasses for simulation of white light

Lead containing barium zinc lithium fluoroborate (LBZLFB) glasses doped with different concentrations of trivalent dysprosium ions were synthesized by conventional melt quenching method and characterized through the XRD, DSC, FTIR, FT-Raman, optical absorption, photoluminescence and decay curve analysis. X-ray diffraction studies revealed amorphous nature of the studied glass matrices. The thermal behavior has been reported by recording DSC thermograms. Coexistence of trigonal BO3 and tetrahedral BO4 units was evidenced by IR and Raman spectroscopy. Judd–Ofelt intensity parameters have been evaluated for 1.0mol% Dy3+ ions doped LBZLFB glass. The measuring branching ratios are reasonably high for transitions 4F9/2→6H15/2 and 6H13/2 suggesting that the emission at 486 and 577nm, respectively can give rise to lasing action in the visible region. From the visible emission spectra, the yellow to blue (Y/B) intensity ratios and chromaticity color coordinates were estimated. A combination of blue and yellow emissions has emerged in the glasses, which allows the observation of white light when the glasses are excited by the ultraviolet/blue light. These Dy3+ doped glasses are studied for their utility for white light generation under 454nm excitation and the present LBZLFB glass is more suitable for generation of white light for blue LED chips.

Structural and luminescence studies on Eu3+: B2O3–Li2O–MO–LiF (M=Ba, Bi2, Cd, Pb, Sr2 and Zn) glasses

The present work reports the structural and luminescence studies on 54B2O3+25Li2O+15MO+ 5LiF+1Eu2O3 (where M=Ba, Bi2, Cd, Pb, Sr2 and Zn) glasses prepared by following melt quenching technique. The influence of the metal ions in the host matrix have been studied by measuring FTIR, absorption, excitation and emission spectra. FTIR studies explore the presence of the functional units in the prepared glasses. Through the optical absorption spectra bonding parameters (β¯, δ), direct and indirect allowed band gap and Urbach energy (ΔE) values were calculated and reported. Due to some defects associated with the addition of various oxides in to the host matrix, the Urbach energy values changes inversely with the optical band gap. The phonon side band have also been observed on the high energy side of the 7F0→5D2 transition in the excitation spectra due to the coupling between the coordination ions and Eu3+ ions. Judd–Ofelt (JO) intensity parameters have been determined from the luminescence spectra and is used to explore the nature of the Eu3+ ions with its surrounding ligands. The JO parameters have been used to calculate the stimulated emission cross-section (σPE), branching ratios (βR) and radiative lifetime (τR) for the 5D0→7FJ (J=1, 2, 3 and 4) transitions of the Eu3+ ions in the prepared glasses. The experimental lifetime of the 5D0 level in the Eu3+ doped lithium fluoroborate glasses have been calculated and reported. The longer lifetime of the 5D0 metastable state indicates that the prepared glasses are suitable for laser applications.

Spectroscopic and laser properties of Sm3+ ions doped lithium fluoroborate glasses for efficient visible lasers

The Sm3+-doped lead barium zinc lithium fluoroborate (LBZLFB) glasses of composition 20PbO+5BaO+5ZnO+10LiF+(60−x) B2O3+xSm2O3, (where x=0.1, 0.5, 1.0, 1.5 and 2.0mol%) have been prepared by conventional melt quenching technique and their structural and spectroscopic behavior were studied and reported. The amorphous nature of these glass samples was confirmed with XRD studies. The FT-IR and FT-Raman spectra reveal that, the glasses contain BO3, BO4, non-bridging oxygen and strong OH bonds. The bonding parameters and the oscillator strengths were determined from the absorption spectra. These parameters have been used to obtain the Judd–Ofelt intensity parameters. Using these intensity parameters various radiative and laser properties were predicted. The values of J–O intensity parameters suggested an increase in the degree of symmetry of the local ligand field at Sm3+ sites. The decay rates for the 4G5/2 level of Sm3+ ions have been measured and are found to be single exponential at lower concentrations (<1.0mol%) and turn into non-exponential at higher concentrations (⩾1.0mol%), due to energy transfer through cross-relaxation. From the emission characteristic parameters of 4G5/2 level, it is concluded that the LBZLFB glasses could be useful for photonic devices like visible lasers, fluorescent display devices and optical amplifiers, operated in the visible region.

Effect of modifier oxides on absorption and emission properties of Eu3+ doped different lithium fluoroborate glass matrices

Eu 3+ doped lithium fluoroborate glass with different modifier oxides (Li 2 B 4 O 7 –BaF 2 –NaF–MO where M=Mg, Ca, Cd and Pb) and combinations of modifier oxides (Li 2 B 4 O 7 –BaF 2 –NaF–MgO+CaO, Li 2 B 4 O 7 –BaF 2 –NaF–CdO+PbO) were prepared by means of melt quenching method. These glass samples were analyzed by absorption, photoluminescence and decay curve measurements. The relative merits of thermal correction to the spectral intensities originating from the ground state ( 7 F 0 ) of different absorption bands of Eu 3+ are calculated. From the optical absorption measurements and using the Judd–Ofelt (J–O) theory, J–O parameters (Ω λ λ =2, 4 and 6) have been obtained which are used to predict the radiative properties such as radiative transition probabilities ( A ), radiative life-times ( τ R ), and branching ratios ( β r ) for certain transitions in all the glass matrices. From the emission spectra, peak stimulated emission cross-sections ( σ P ) are obtained for the emission transitions, 5 D 0 → 7 F 1 , 5 D 0 → 7 F 2 , 5 D 0 → 7 F 3 and 5 D 0 → 7 F 4 of Eu 3+ in lithium fluoroborate glass matrix with different modifier oxides. The fluorescence decay curves of the 5 D 0 → 7 F 2 transition have been measured and analyzed for all the glass matrices.

Influence of modifier oxides on spectroscopic properties of Sm3+ doped lithium fluoroborate glass

Sm3+ doped lithium fluoro-borate glasses with different modifier oxides (Li2B4O7–BaF2–NaF–MO where M=Mg, Ca, Cd and Pb) and combinations of modifier oxides (Li2B4O7–BaF2–NaF–MgO+CaO, Li2B4O7–BaF2–NaF–CdO+PbO) were prepared by means of melt quenching method. These samples were characterized by XRD, FTIR, optical absorption and fluorescence techniques at room temperature. The XRD profiles of all the glasses confirm their amorphous nature and the FTIR spectra reveal the presence of BO3 and BO4 units along with the strong OH− groups in the glass matrices. The influence of modifier oxides on Judd–Ofelt (J–O) intensity parameters and intensity of the emission lines are reported. Judd–Ofelt theory is used to study the spectral properties and to calculate the radiative transition probabilities (AT), branching ratios (βR), integrated absorption cross sections (Σ) and radiative lifetimes (τR) for certain spectral transitions. From the emission spectral analysis, emission cross-sections (σP) are calculated for the four emission transitions, 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2 and 4G5/2→6H11/2 of Sm3+ ion in different lithium fluoro-borate glasses. Among the four transitions, it is observed that the transition 4G5/2→6H7/2 has higher emission cross-section (σP) in all the glass matrices, except in Mg, Cd and Mg–Ca glass matrices. The non-exponential nature of the luminescence decay curves of 4G5/2 level of Sm3+ doped glass matrices are also reported.