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The visible luminescence of Pr3+ and Tm3+ ions in lead borate glasses has been investigated as a function of activator concentration. The Judd–Ofelt analysis and the Inokuti–Hirayama model for energy transfer between activator ions have been applied for investigations of the radiative and non-radiative relaxation of the Pr and Tm excited states. Based on the luminescence decay curve analysis, the concentration quenching of the 1D2 emission of Pr3+ and 1G4 emission of Tm3+ ions has been attributed to cross-relaxation processes. The infrared spectroscopic measurements provide information on structural changes in the borate network initiated by optically active (Pr or Tm) ions. Contrary to the praseodymium ions, the thulium ions play an additional role as a glass-modifier in the PbO–B2O–Al2O3–WO3 composition.

The effect of erbium concentration on thermal stability and quantum efficiency of excited states was studied using DSC, XRD and optical methods. A large value of stability parameter Δ T close to 118 °C has been obtained for fluoroindate glass singly doped with 2 mol% of erbium ions. With increasing erbium concentration stability parameter extremely decreased and several crystalline peaks appeared, what was stated by X-ray diffraction. Also, the strong luminescence quenching is observed. This behavior is consistent with nonradiative processes related to the Er–Er interaction.

Compositional-dependent heavy metal lead borate glasses doped with Tb3+ ions were investigated. Green luminescence related to main 5D4→7F5 (543 nm) transition was registered under excitation of 5D3 state of Tb3+ ions. Based on excitation and luminescence measurements, several spectroscopic parameters for Tb3+ ions were examined as a function of heavy metal PbO content. Luminescence decay analysis indicated that the 5D4 luminescence lifetime of Tb3+ reduced from 2.83 to 1.42 ms, when PbO:B2O3 ratio was changed from 1:1 to 4:1.

Heavy metal lead germanate glasses doubly doped with Yb 3+ and Ln 3+ ions (Ln=Er, Tm) were investigated. Up-conversion spectra of Er 3+ and Tm 3+ were registered under diode-laser excitation of Yb 3+ . Up-conversion luminescence bands corresponded to 4 S 3/2 → 4 I 15/2 (green) and 4 F 9/2 → 4 I 15/2 (red) transitions of Er 3+ as well as 1 G 4 → 3 H 6 (blue) and 3 H 4 → 3 H 6 (NIR) transitions of Tm 3+ , respectively.

Visible luminescence of Dy(3+) ions in oxyhalide lead borate glasses was examined. Luminescence spectra show two intense bands at 480 nm and 573 nm due to (4)F(9/2)→(6)H(15/2) (blue) and (4)F(9/2)→(6)H(13/2) (yellow) transitions of Dy(3+). Luminescence decays from (4)F(9/2) state and yellow-to-blue luminescence intensity ratios (Y/B) were analysed with PbX(2) (X=F, Cl) content. An introduction of PbX(2) to the borate glass results in the increasing of (4)F(9/2) lifetime and the decreasing of yellow-to-blue luminescence intensity ratio, which is due to reduction of covalency between Dy(3+) and O(2-)/X(-) ions.

Influence of M 2 O 3 (M = Al, Ga) modifiers oxide on local structure and spectroscopic properties of lead phosphate glasses containing rare earth ions was studied. Among the rare earths, the trivalent europium and erbium ions were selected as an optically active dopants. The thermal properties were examined using DSC, whereas the X-ray diffraction analysis was used in order to verify the structure glass matrix. Luminescence of rare earth ions in lead phosphate glasses was registered in visible and NIR spectral region. The excitation and emission spectra of lead-based systems are presented and discussed in relation to the effect of modifiers oxide M 2 O 3 (M = Al, Ga). Luminescence lifetimes (τm) for the 5 D 0 state of Eu 3+ ions and 4 I 13/2 state of Er 3+ ions were also evaluated.

Optical properties of Pr3+ ions in lead-free germanate glasses modified by BaF2 were investigated. Luminescence bands related to 3P 0 → 3 H 4 , 3 P 0 → 3 H 5 , 1 D 2 → 3 H 4 , 3 P 0 → 3 H 6 , 3 P 0 → 3 F 2 transitions of Pr 3+ were registered under 450 nm excitation. The relative integrated luminescence intensities of 3P0 → 3H4 transition (blue) to the 3 P 0 → 3 F 2 transition (red) of Pr 3+ ions strongly depend on fluoride modifier BaF2 in glass composition. The blue-to-red luminescence intensity ratios of Pr 3+ are drastically reduced, when BaO is partially substituted by BaF2. The luminescence lines due to 3 P 0 → 3 F 2 hypersensitive transition of Pr 3+ are blue shifted with increasing BaF 2 concentration.

Lead-free germanate glasses doped with rare earth ions were synthesized and next studied using excitation and luminescence spectroscopy. Rare earths were limited to Pr3+, Eu3+ and Er3+ ions. Several luminescence bands correspond to transitions originating from the 3P0 and 1D2 states of Pr3+, the 5D0 state of Eu3+, the 4S3/2, 4F9/2 and 4I13/2 states of Er3+, respectively. The relatively long lifetime for the upper 4I13/2 laser state of Er3+ suggest that lead-free germanate glasses are promising materials for near-infrared optical amplifiers.

Excitation and luminescence properties of Eu3+, Tb3+ and Er3+ ions in lead phosphate glasses have been studied. From excitation spectra of Eu3+ ions, the electron–phonon coupling strength and phonon energy of the glass host were calculated and compared to that obtained by Raman spectroscopy. Main intense and long-lived luminescence bands are related to the 5D0–7F2 (red) transition of Eu3+, the 5D4–7F5 (green) transition of Tb3+ and the 4I13/2–4I15/2 (near-infrared) transition of Er3+. The critical transfer distances, the donor–acceptor interaction parameters and the energy transfer probabilities were calculated using the fitting of the luminescence decay curves from 5D0 (Eu3+), 5D4 (Tb3+) and 4I13/2 (Er3+) excited states. The energy transfer probabilities for Eu3+ (5D0), Tb3+ (5D4) and Er3+ (4I13/2) are relatively small, which indicates low self-quenching luminescence of rare earth ions in lead phosphate glasses.

Dy-doped lead borate glasses were studied. The luminescence spectra showed two characteristic bands at 480 and 573 nm due to 4 F 9/2 – 6 H 15/2 (blue) and 4 F 9/2 – 6 H 13/2 (yellow) transitions of Dy 3+ . The yellow/blue luminescence of trivalent dysprosium was analyzed as a function of the B 2 O 3 /PbO ratios, the activator (Dy 3+ ) and the PbX 2 (X = F, Cl, Br) content.

Transparent glass-ceramics were successfully prepared during controlled heat treatment of lead borate glasses. The PbF 2 particles were dispersed into a borate glass matrix which was evidenced by X-ray diffraction analysis. The phase identification revealed that crystalline peaks can be related to the ortho-rhombic PbF 2 phase. Green up-conversion luminescence due to the 4 S3/2- 4 I 15/2 transition of Er3+ ions was registered. In comparison to the precursor glass the luminescence intensity was considerably higher, whereas the luminescence linewidth slightly decreased in the studied oxyfluoride transparent glass-ceramics. It indicated that a part of the trivalent erbium was incorporated into the PbF 2 crystalline phase.

Near-infrared luminescence spectra at 1.53 μm due to main 4 I 13/2 – 4 I 15/2 laser transition of Er 3+ ions in oxide and oxyhalide lead borate glasses were examined. Spectroscopic parameters like spectral linewidth and luminescence lifetime were analyzed with PbX 2 (X = F, Cl or Br) doping. An introduction of lead halide to the borate glass results in the reduction of spectral linewidth and the increase of luminescence lifetime of Er 3+ . The luminescence decay from the 4 I 13/2 upper state of Er 3+ is longer for glass sample with PbF 2 than PbX 2 (X = Cl or Br).

Structural behavior and luminescence properties of rare earth ions (Pr3+, Eu3+, Er3+) in oxide and oxyfluoride lead borate glasses have been studied using X-ray diffraction and spectroscopic methods. Substitution of PbO by PbF2 results in decreasing of the number of tetrahedral BO4 units, which was observed for Pr3+ and Eu3+ ions in lead borate glasses using infrared spectroscopy. In contrast to oxyfluoride lead borate glasses, several diffraction lines due to crystalline ErBO3 phase were identified for Er-doped oxide sample. Luminescence spectra for rare earth ions in lead borate based glasses have been analyzed, where PbO was totally substituted by PbF2.

Fluorescence at 1.06 μm due to main 4 F 3/2 – 4 I 11/2 laser transition of Nd 3+ ions in multicomponent B 2 O 3 –PbF 2 –PbO–Al 2 O 3 –WO 3 glass system has been registered and some laser parameters for Nd 3+ ions have been evaluated. The Nd-doped oxyfluoroborate glasses have been investigated as a function of PbF 2 concentration and thermal treatment. The fluorescence decays from 4 F 3/2 excited state of Nd 3+ ions are independent on PbF 2 concentration. The orthorhombic PbF 2 phase has been identified for Nd-doped transparent glass-ceramics obtained after thermal treatment.

The efficient non-resonant energy transfer from Yb 3+ to Tm 3+ ions in lead fluoroborate glasses has been observed. Up-converted luminescence due to 3 H 4 – 3 H 6 transition of Tm 3+ ions has been registered under excitation of Yb 3+ ions at 975 nm. From luminescence decay analysis some parameters have been determined using Inokuti–Hirayama model. The results were compared to those recorded with singly Yb-doped samples in order to clarify the energy transfer process.

Spectroscopic properties of rare earths in lead-free oxyfluoride germanate glasses were studied. The absorption and luminescence spectra of Eu(3+), Pr(3+) and Er(3+) ions were examined as a function of BaF₂ concentration and several spectroscopic parameters for rare earths were determined. The ratio of integrated luminescence intensity of the (5)D₀→(7)F₂ transition to that of the (5)D₀→(7)F₁ transition of Eu(3+) decrease significantly with increasing BaF₂ content. The absorption (Er(3+)) and emission (Pr(3+)) 'hypersensitive transitions' of rare earths are shifted in direction to shorter wavelengths with increasing BaF₂ content in glass composition. Emission spectra and their decays corresponding to the main (4)I₁₃/₂→(4)I₁₅/₂ laser transition of Er(3+) were also analyzed. Quite long-lived NIR luminescence of Er(3+) is observed for lead-free glass samples with low BaF₂ concentration.

In this paper, upconversion (UC) luminescence processes in a GeO2−Ga2O3−BaO glass system codoped with 0.7Yb2O3/(0.07−0.7)Tb2O3 (mol.%) and double-clad optical fiber codoped with 0.7Yb2O3/0.7Tb2O3 (mol.%) were investigated. The highest emission intensity (energy transfer efficiency equals 12.92%) was obtained for 0.7Yb2O3/0.7Tb2O3 codoped glass. Comparative analysis showed significant differences in the shape of luminescence of fabricated germanate glass and optical fiber. Due to dominant transition from D45 sublevel the main green UC peak (Tb3+: D45→F57) of fabricated double-clad optical fiber is shifted by 4 nm toward longer wavelengths.

Heavy metal oxide and oxyhalide glasses containing Er 3+ ions have been investigated. Near-infrared luminescence at about 1550 nm and up-conversion spectra of Er 3+ ions were registered under excitation by 980 nm diode laser line. Several luminescence bands are observed, which correspond to the 4 I 13/2 - 4 I 15/2 (1550 nm), 2 H 11/2 , 4 S 3/2 - 4 I 15/2 (550 nm), 4 F 9/2 - 4 I 15/2 (670 nm) and 4 I 9/2 - 4 I 15/2 (800 nm) transitions of Er 3+ , respectively. The optical transitions of Er 3+ ions have been examined as a function of glass host and PbX 2 (X = F, Cl, Br) content.

Lead phosphate glasses containing rare earth ions were prepared in a glow box in order to minimize concentration of hydroxyl groups. Rare earths as an optically active ions were limited to Eu 3+ , Dy 3+ , Tb 3+ and Er 3+ . Luminescence of rare earth ions in lead phosphate glasses was registered in visible spectral region. Luminescence bands correspond to 5 D 0 - 7 F J (J = 0 ÷ 4) transitions of Eu 3+ ions, 4 F 9/2 - 6 H J/2 (J = 11, 13, 15) transitions of Dy 3+ ions, 5 D 3 - 7 F J' (J' = 1 ÷ 6) and 5 D 4 - 7 F J (J = 3 ÷ 6) transitions of Tb 3+ ions, and 4 S 3/2 - 4 I 15/2 transitions of Er 3+ ions, respectively. Luminescence decays from excited states of rare earth ions have been analyzed in details.

Lead phosphate glasses containing Eu(3+) and Dy(3+) have been studied. Local structure was verified using Fourier transform (FT)-IR spectroscopy. Emission bands of Eu(3+) and Dy(3+) ions in lead phosphate glasses are observed in the visible spectral range, which correspond to 5D0→7F(J) (J=0,1,2,4) and 4F(9/2)→6H(J/2) (J=15,13,11) transitions, respectively. Shorter luminescence decays from excited states of Eu(3+) and Dy(3+0 are due to the presence of PbO in phosphate glass.

Selected oxyfluoride glasses containing Eu 3+ and Dy 3+ were heat treated in order to obtain transparent glass-ceramics. Visible emission spectra corresponding to 5 D 0 - 7 F J (J = 0, 1, 2, 3, 4) transitions of Eu 3+ and 4 F 9/2 - 6 H J/2 (J = 11, 13, 15) transitions of Dy 3+ in glass samples before and after heat treatment were registered. The luminescence intensity ratios R (Eu 3+ ) and Y/B (Dy 3+ ) have been analyzed in details. Their values are reduced due to part incorporation of rare earth ions into cubic β-PbF 2 crystalline phase.

Selected heavy metal glasses containing Yb 3+ and Er 3+ ions have been investigated. Near-infrared luminescence spectra at 1.53 μm and up-conversion spectra of Er 3+ were registered under excitation of Yb 3+ by 975 nm diode laser line. The luminescence bands correspond to 4 I 13/2 - 4 I 15/2 (NIR), 4 S 3/2 - 4 I 15/2 (green) and 4 F 9/2 - 4 I 15/2 (red) transitions of Er 3+ , respectively. The optical transitions of rare earth ions have been examined as a function of glass host.

Spectroscopic properties of a fabricated double – clad, off-set core antimony - germanate optical glass fiber co-doped with Yb3+/Ho3+ has been investigated. Upconversion luminescence of holmium ions at the wavelengths of 549 nm (5S2 (5F4) → 5I8) and 658 nm (5F5 → 5I8) was obtained as a result of the energy transfer between Yb3+ and Ho3+ ions. Glass characterized by highest intensity of upconversion luminescence (1Yb2O3/0.5Ho2O3 mol%) was used as core of double-clad optical fiber. Upconversion amplified spontaneous emission in the fabricated double – clad, off-set core optical fiber was obtained. The intensity emission ratio red (5F5→5I8)/green (5S2 (5F4)→5I8) of the fabricated optical fiber is several times higher than in bulk glass. Reabsorption of the ASE signal along the fiber resulting from Ho3+: 5S2(5F4) → 5I8,5F5 → 5I8 transitions transition was observed.

Heavy metal fluoride glasses of the following composition: 35.5InF3-16BaF2-20ZnF2-20SrF2-6GaF3-2NaF-0.5PrF3 (IZBSGN05Pr) and 35.5InF3-16BaF2-20ZnF2-20SrF2-6GaF3-2NaF-0.5TmF3 (IZBSGN05Tm) have been studied. Obtained fluoroindate glasses have been submitted to controlled crystallization. The crystallite size was determined by Scherrer equation and the Williamson-Hall analysis. In those studies X-ray diffraction (XRD) and luminescence measurements have been employed.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Structural and optical behavior of Pr-doped lead fluoroborate glass has been investigated. Incorporation of PbF 2 results in structural and optical changes around Pr 3+ ions and surrounding ligands, which were analyzed using X-ray diffraction, Raman, IR and luminescence spectroscopy. Shift of spectral lines has been observed, when lead oxide is totally substituted by lead fluoride in glass composition. Luminescence corresponding to the 1 D 2 – 3 H 4 transition of Pr 3+ ions has been detected. The peak luminescence wavelength is changed from 604 nm to 599 nm and linewidth decreases from 23.5 nm to 18 nm, whereas the infrared bands due to the B – O vibrations are shifted to lower frequency region. Keywords: lead fluoroborate glasses, Pr 3+ ions, short-range order structure, luminescence properties 1. INTRODUCTION Rare earth – doped lead fluoroborate glasses belong to the modern optoelectronic materials, which are interesting from the optical and structural points of views. Firstly, they have been extensively studied in relation to the practical application as laser materials, optical fibers and infrared-to-visible convertors. Secondly, the great number of possible borate units in this glass system is very attractive for structural investigations. Recently, lead fluoroborate glasses singly doped with Nd

Selected oxyfluoride glasses and glass-ceramics have been investigated. NIR luminescence at 1.06 μm and 1.53 μm for Nd3+ and Er3+ ions in multicomponent oxyfluoride systems was registered, which correspond to the main 4F3/2 - 4I11/2 and 4I13/2 - 4I15/2 laser transitions, respectively. Influence of PbF2 concentration and heat treatment on NIR luminescence decay kinetics has been analyzed in detail.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Rare earth - doped heavy metal glasses (HMG) are one of the most important optical systems, which can be used for the design of solid-state laser materials and fiber light sources. Among the numerous heavy metal systems, erbium - doped lead borate glass exhibits quite large stimulated emission cross-section and broad fluorescence width at half maximum (FWHM) at 1.55 /spl mu/m band due to /sup 4/I/sub 13/2/ - /sup 4/I/sub 15/2/ transition, which is eye-safe and used for infrared optical telecommunication system. Spectroscopic properties of erbium - doped oxyfluoride lead borate glasses in multicomponent PbO - PbF/sub 2/ - B/sub 2/O/sub 3/ - Al/sub 2/O/sub 3/ - WO/sub 3/ system were investigated. The spectral linewidth analysis for main near-infrared emission spectra of the /sup 4/I/sub 13/2/ - /sup 4/I/sub 15/2/ transition and the luminescence decay curve measurements of the /sup 4/I/sub 13/2/ excited level of Er/sup 3+/ were performed.

A challenge to invent the material of a glass-ceramics type with a network of nanocrystals in the glassy matrix by means of a glass controlled crystallization is presented in the paper. The structures occur at the time of a glass heat treatment. The studies were carried out on fluoroindate glasses doped with rare-earth elements. Controlled crystallization was performed in order to obtain transparent glass-ceramics: the network of nanocrystallites (or at least microcrystallites) with higher content of rare earth ions in comparison to their content in the glassy matrix. In order to compare the initial glass and the new material of a glass-ceramics type properties, several experimental techniques were emloyed like X-ray diffraction (XRD), electron probe microanalysis (EPMA), differential thermal analysis (DTA), differential scanning calorimetry (DSC) and luminescence measurements.

Optical absorption and emission spectra of Eu3+ ions in fluoroindate glasses have been investigated. From the experimental values of oscillator strengths with thermal correction, the Judd-Ofelt intensity parameters were obtained. These data are compared with Judd-Ofelt parameters also calculated from emission spectra. The spectroscopic parameters of Eu3+ ions in fluoroindate glasses were determined and compared to the values of fluorozirconate glasses.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The InF3-based fluoride glasses doped with Tm3+ and Tm3+-Tb3+ ions were studied by x-ray diffusion, differential scanning calorimetry and optical spectroscopy. The thermal stability and luminescence quenching of Tm+3 ions in InF3-glass have been investigated as a function of activator concentration. In the limit of low activator concentration, values of stability parameter and quantum efficiency of excited states are very high, suggestion their practical application of those glasses in optical devices.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Up-conversion luminescence processes of Tb3+ ions in GeO2-Ga2O3-BaO glass system were investigated under diode-laser excitation of Yb3+. Emission bands at 489, 543, 586 and 621nm corresponding to 5D4→7FJ (J = 6, 5, 4, 3) transitions and luminescence at 381, 415, 435 nm resulting from 5D3, 5G6→7FJ (J = 6, 5, 4) transitions of Tb3+ were observed. The highest up-conversion emission intensity was obtained for 0.7Yb2O3/0.7Tb2O3 co-doped lead-free germanate glass. The energy transfer coefficient was determined based on fitting of calculations and experimental results by least squares method. The energy transfer coefficient amounts to Cf = 1.5∙10−33 cm6/s while quantum efficiency of the Yb3+→Tb3+ energy transfer is 12%.

The luminescence properties of selected rare-earth ions in lead silicate glasses have been studied. Europium, dysprosium and terbium ions were chosen as active dopants. Based on excitation and emission measurements as well as luminescence decay analysis, some spectroscopic parameters for these lanthanide ions were determined. In particular, the intensity ratios R/O (Eu3+), Y/B (Dy3+) and G/B (Tb3+) were calculated. Luminescence lifetimes for the 5D0 state of Eu3+ ions, the 4F9/2 state of Dy3+ ions and the 5D4 state of Tb3+ ions were also determined.

Blue and green luminescence spectra of Tb3+ ions in lead phosphate glasses were examined under UV excitation. The green-to-blue luminescence intensity ratio G/B is considerably reduced with decreasing Tb3+ concentration. Thus, blue emission lines are enhanced in comparison to the main 5D4-7F5 green transition of Tb3+. These effects strongly depend on terbium-terbium interactions in lead phosphate glasses. It was confirmed by luminescence decay curve analysis and calculations using the Inokuti-Hirayama model.

Optical properties of lead borate glasses containing Dy(3+) ions were examined using absorption and luminescence measurements and theoretical calculations based on the Judd-Ofelt framework and the Inokuti-Hirayama model. The luminescence spectra show two characteristic bands at 480 and 573 nm, which are due to (4)F(9/2)-(6)H(15/2) (blue) and (4)F(9/2)-(6)H(13/2) (yellow) transitions of trivalent Dy(3+) ions. The yellow/blue luminescence and its decay were analyzed as a function of activator concentration.