2-μm fluorescence and Raman spectra in high and low Al(PO3)3 content fluorophosphates glasses doped with Er-Tm-Ho

Thermal stability and 2-μm fluorescence of high and low Al(PO_3)_3 content of fluorophosphate glasses are investigated.Thermal stability of high Al(PO_3)_3 content of fluorophosphate glass is better than low Al(PO_3)_3 content of fluorophosphate glass.However, 2.04-μm fluorescence intensity of high Al(PO_3)_3 content of fluorophosphate glass is only 48.2, lower than low Al(PO_3)_3 content of fluorophosphate glass.Raman spectroscopy is employed to investigate the difference in thermal stability and 2-μm fluorescence.Moreover, fluorescence peak intensity ratios of 2.04 to 1.81 μm and 2.04 to 1.57 μm are calculated, which indicate that Er-Tm-Ho doped fluorophosphate glasses are suitable materials in 2-μm applications.     

Enhancement of upconversion luminescence of YAlO3：Er^3＋ by Gd^3＋ doping

Two series of Yb3+-doped silica glasses (YA and YAP) are fabricated using the sol-gel method, and their spectroscopic properties are investigated. The longest fluorescence lifetime of 0.96 ms is obtained in YAP2 and YAP3 glasses. The emission cross-section (σemi) and σemi ×τ of Yb3+ in the YAP1 glass are 1.00 pm2 and 0.94 pm2·ms, respectively. Co-doping with Al and P decreases the hydroxyl group content in the glasses because of the reduction in non-bridging oxygen content. The lowest OH content in the YAP3 glass is 9.6 ppm.     

Spectroscopic properties in Er3＋/yb3＋ Co-doped fluorophosphate glass

Using the technique of high-temperature melting, a new Er3＋/Yb3＋ co-doped fluorophosphate glass was prepared. The absorption and fluorescence spectra were investigated in depth. The effect of Er3＋ and Yb3＋ concentration on the spectroscopic properties of the glass sample was also discussed. According to the Judd Ofelt theory, the oscillator strength was computed. The lifetime of 4113/2 level （t-m） of Er3＋ ions was 8.23 ms, and the full width at half maximum of the dominating emission peak was 68 nm at 1.53 μm. The large stimulated emission cross section of the Er3＋ was calculated by the McCumher theory. The spectroscopic properties of Er3＋ ion were compared with those in different glasses. The full width at half maximum and σe are larger than those of other glass hosts, indicating this studied glass may be a potentially useful candidate for high-gain erbium-doped fiber amplifier.     

Tm^3＋-doped Ga2O3-GeO2-Bi2O3-PbO（PbF2） Glasses for 1.47-μm Optical Amplifications

We report the spectroscopic properties and thermal stability of Tm^3＋-doped Ga2O3-GeO2-Bi2O3-PbO（PbF2） glasses for 1.47-μm optical amplifications. Effects of PbF2 doping on the optical properties and thermal stability of Tm^3＋ -doped gallate-germanium-bismuth-lead glass are inestigated. The measured peak wavelength and full width at half-maximum of the fluorescence are 1465nm and - 120 nm, respectively： Siguificant enhancement of the 1.47-μm emission and the lifetime of a a^3H4 level with increasing PbF2 doping have been observed. The presence of GeO2 provides two potentials of increasing the thermal stability and shortening the ultraviolet cutoff band of host glasses.     

Composition Dependence of Spectroscopic Properties of Er^3＋ Doped TeO2-WO3-ZnO Glasses

Er^3 -doped TeO2-WO3-ZnO glasses were prepared and the absorption spectra, emission spectra and fluorescence lifetimes were measured. With more Te02 content in the glasses, the emission full width at half maximum (FWHM) increases while the lifetime of the ^4I13/2 level of Er^3 decreases. The stimulated emission cross-sectionof Er^3 calculated by the McCumber theory is as large as 0.86pm^2. The product of the FWHM and the emissioncross-section σe of Er^3 in TeO2-WO3-ZnO glass is larger than those in other glasses, which indicates that the glasses are promising candidates for Er^3 -doped broadband amplifiers. The Judd-Otfelt parameter Ω6 shows close composition dependence of the 1.5μm emission bandwidth. The more the TeO2 content is, the larger thevalues of Ω6 and FWHM.     

Emission enhancement in Er^3＋/Pr^3＋-codoped germanate glasses and their use as a 2.7-μm laser material

Emission enhancement at 2.7 μm is observed in Er^3＋/Pr^3＋--codoped germanate glasses when pumped by a 980-nm laser diode. Significant reductions in 1.5-μm emission and upeonversion intensity indicate efficient energy transfer between Er^3＋ and Pr^3＋; the energy transfer efficiency is as high as 77.4%. The mechanisms of energy transfer are discussed in detail. The calculated emission cross-section of Er^3＋/Pr^3＋- codoped germanate glass is 8.44× 10 ^-21 cm^2, which suggests that Er^3＋/Pr^3＋-codoped germanate glass can be used to achieve efficient 2.7-μm emission.     

Broadband and High Efficient 1530 nm Emission from Oxyfluoride Glass Ceramics Codoped with Er3＋ and Yb3＋ Ions

The emission at 1530nm and its applications in optical communications are discussed. The efficient width of the emission band △eff, which is up to 91 nm, is larger as compared with silica-based glass, bismuth glass and ZrF4-BaF2-LaFa-AIF3-NaF （ZBLAN） glass doped by Er^3＋ ions. Under the excitation of 785 nm laser, the emission integral intensity of 153Onto increases about five times in the glass ceramics higher than that in the glass. This is explained by the quantum cutting process by two-photon emission with phonon assistance. The results indicate that the glass ceramics are a promising candidate for developing broadband optical amplifiers in wavelength-division multiplexed systems.     

2-μm emission performance of Tm~(3+)-Ho~(3+) co-doped tellurite glasses

The emission properties of 2-μm region fluorescence of Tm~(3+)-Ho~(3+) co-doped tellurite glasses are investigated. Introducing F~- ions to the composition of tellurite glasses plays a positive effect on the 2-μm emission.A maximum intensity of 2-μm emission is achieved when 1.5-mol%Tm_2O_3 and l-mol% Ho_2_O3 concentration are doped in the glasses.The emission cross section and gain coefficient of the ~5I_8→~5I_7 transition of Ho~(3+) are calculated.The emission cross section has a maximum of 1.29×10~(-2...     

Spectral Properties of Erbium—Doped Oxyfluoride Silicate Glasses for Broadband Optical Amplifiers

The new oxyfluoride silicate glasses of Er^3 -doped 50SiO2-(50-x) PbO-xPbF2 were prepared. With increasing PbF2 content in the glass composition, the fluorescence full width at half maximum and lifetimes of the ^4I13/2 level of Er^3 increase, while the refractive indices and densities decrease. Er^3 -doped 50SiO2-50PbF2 glass showed broad fluorescence spectra of 1.55μm with a large stimulated emission cross-section and long lifetimes of ^4I13/2 level of Er^3 . Compared with other glass hosts, the gain bandwidth properties of Er^3 -doped 50SiO2-50PbF2 glass are close to those of tellurite and bismuth glasses, and have advantages over those of silicate, phosphate and germante glasses. The broad and flat ^4I13/2→^4I15/2 emission of Er^3 around 1.55μm can be used as host material for potential broadband optical amplifier in wavelength-division-multiplexing network system.     

Broadband 1.5-μm emission of erbium-doped TeO2-WO3-Nb2O5 glass for potential WDM amplifier

Erbium-doped glass showing the wider 1.5-/μm emission band is reported in a novel oxide system TeO2-WO3-Nb2O5 and their thermal stability and optical properties such as absorption,emission spectra,cross-sections and fluorescence lifetime were investigated.Compared with other glass hosts,the gain bandwidthproperties of Er3+ in TWN glass is close to that of bismuth glasses,and larger than those of tellurite,germanatc,silicate and phosphate glasses.The broad and flat 4I13/2 → 4I15/2 emission and the largestimulated emission cross-section of Er3+ ions around 1.5 μm can be used as host material for potentialbroadband optical amplifier in the wavelength-division-multiplexing(WDM)network system.     

Mid-infrared luminescence of Dy~(3+)-doped Ga_2S_3–Sb_2S_3–CsI chalcohalide glasses

The mid-infrared(MIR) luminescent properties of Dy~(3+) ions in a new chalcohalide glass host, Ga_2S_3–Sb_2S_3–CsI,are investigated; and the suitability of the doped glass for MIR fiber lasers is evaluated. The Dy~(3+)-doped chalcohalide glasses exhibit good thermal stability and intense MIR emissions around 2.96 μm and 4.41 μm. These emissions show quantum efficiencies(η) as high as ~60%, and have relatively large stimulated emission cross sections(σem). The low phonon energy(~307 cm~(-1)) of the host glass accounts for the intense MIR emissions, as well as the high η. These favorable thermal and emission properties make the Dy~(3+)-doped Ga_2S_3–Sb_2S_3–CsI glasses promising materials for MIR fiber amplifiers or lasers.     

Synthesis and third-order nonlinear optical property of poly（urethane-imide）

The poly（urethane-imide） （PUI） which uses isophorone diisocyanate, dispersed red 19 （DR-19）, and py- romellitic dianhydride is synthesized. The PUI is characterized by Fourier transform infrared （FT-IR） spectroscopy, differential scanning calorimetry （DSC）, and thermogravimetric analysis （TGA）. The results of DSC and TGA indicate that the PUI exhibits high thermal stability up to its glass-transition temperature of 209 ℃ and 5° heat weight loss temperature of 296℃. The fluorescence spectra of PUI and DR-19 are measured, showing that the fluorescence effect of PUI is very similar to that of DR-19 except for the light decrease of fluorescence intensity, which indicates that the fluorescence effect of PUI is generated by the azobenzene groups in its macromolecular chains. The maximum molar absorption coefficient, absorp- tion wavelength, and chromophores density are measured and used to calculate the third-order nonlinear optical coefficient X（3） to be 3.96×10^-13 esu. The nonlinear refractive index coefficient and molecular hyperpolarizabilitv of PUI are also obtained. PUI is oroved to have an excellent ootical Performance.     

Intense Green Upconversion Luminescence in Er^3＋：Yb^3＋ Codoped Fluorophosphate Glass Ceramic Containing SrTe5O11 Nanocrystals

Er^3＋ ：Yb^3＋ codoped tellurite-fluorophosphate （TFP） glass ceramic exhibits much stronger upconversion luminescence. The intensity of the 540nm green light and 651 nm red light of the TFP glass ceramic is 120 times and 44 times stronger than that of the fluorophospahte （FP） glass, respectively. XRD analysis shows that the nanocrystal in TFP glass ceramic is SrTe5O11. TFP glass ceramic also displays much higher upconversion fluorescence lifetime and crystallization stability. The narrow and strong peak at 540nm is very ideal for practical upconversion luminescence realization. This work is a new trial for exploring non-PbF2 involved nanocrystal upconversion glass ceramics.     

Broadband 1.5-um emission of erbium-doped TeO_2-WO_3-Nb_2O_5 glass for potential WDM amplifier

Erbium-doped glass showing the wider 1.5-um emission band is reported in a novel oxide system TeO2-WO3-Nb2O5 and their thermal stability and optical properties such as absorption, emission spectra, cross-sections and fluorescence lifetime were investigated. Compared with other glass hosts, the gain bandwidth properties of Er3+ in TWN glass is close to that of bismuth glasses, and larger than those of tellurite, germanate, silicate and phosphate glasses. The broad and flat 4I13/2-4I15/2 emission and the large stimulated emission cross-section of Er3+ ions around 1.5um can be used as host material for potential broadband optical amplifier in the wavelength-division-multiplexing (WDM) network system.     

Er^3＋/Tm^3＋/Yb^3＋ tridoped oxyfluoride glass ceramics with efficient upconversion white-light emission

A novel Tm^3＋/Yb^3＋ triply-doped glass ceramics containing BaF2 nano-crystals are successfully prepared. Fluoride nanocrystals BaF2 are successfully precipitated in glass matrix, which is affirmed by the X-ray diffraction results. The intense blue （476 nm）, green （543 nm）, and red （656 nm） emissions of the glass ceramics are simultaneously observed at room temperature under 980-am excitation, and the emission luminescence intensity increases significantly compared with the precursor glass, which is attributed to the low phonon energy of fluoride nanocrystals when rare-earth ions are incorporated into the precipitated BaF2 nanocrystals. Under 980-nm excitation at 400 mW, the international commission on illumination （CIE） chromaticity coordinate （X = 0.278, Y = 0.358） of the tridoped oxyfluoride glass ceramics＇ upconversion emissions is close to the standard white-light illumination （X = 0.333, Y= 0.333）. The results indicate that Tm^3＋/Yb^3＋ triply doped glass ceramics can act as suitable materials for potential three-dimensional displays applications.     

Fluorescence Lifetime Increasing with F- Ions into Ytterbium-Doped Germanium-Lead-Tellurite Glasses

The effects of F^- ions in a germanium-lead-tellurite glass system on the spectral and potential laser properties of the Yb^3 are investigated. The absorption spectra, lifetimes, the emission cross-sections and the minimum pump intensities of the glass system with and without F^- ions have been measured and calculated. The results show that the fluorescence lifetime and the minimum pump intensity of Yb^3 ions increase evidently, which indicatesthat germanium-lead-oxyfluoride tellurite glass is a promising laser host matrix for high power generation. FT-IRspectra were used to analyse the effect of F^- ions on OH^- groups in this glass system. Analysis demonstrates that addition of fluoride removes the OH^- groups and results in improvement of fluorescence lifetime of Yb^3 .     

Sr3Bi（PO4）3：Eu^2＋ Luminescence,Concentration Quenching and Crystallographic Sites

A blue emitting phosphor Sr3Bi（PO4）3：Eu2＋ is synthesized luminescent property is investigated. Sr3Bi（PO4 ）3 ：Eu^2＋ can by a high-temperature solid state method, and its create blue emission under the 332 radiation excitation, and the prominent luminescence in blue （423nm） due to the 4fSd^1→4f^7 transition of the Eu^2＋ ion. The crystallographic sites of the Eu^2＋ ion in Sr3Bi（PO4）3 are analyzed, and the 420 and 440 nm emission peaks of the Eu^2＋ ion are assigned to the nine-coordination and eight-coordination, respectively. The emission intensity of Sr3Bi（PO4）3：Eu^2＋ is influenced by the Eu^2＋ doping content, and the concentration quenching effect is observed. The quenching mechanism is the dipole-dipole interaction, and the critical distance of energy transfer is calculated by the concentration quenching method to be approximately 1.72nm.     

Spectroscopic properties in Er³⁺/Yb³⁺ Co-doped fluorophosphate glass

Using the technique of high-temperature melting, a new Er 3+ /Yb 3+ co-doped fluorophosphate glass was prepared. The absorption and fluorescence spectra were investigated in depth. The effect of Er 3+ and Yb 3+ concentration on the spectroscopic properties of the glass sample was also discussed. According to the Judd–Ofelt theory, the oscillator strength was computed. The lifetime of 4 I 13/2 level (τ m ) of Er 3+ ions was 8.23 ms, and the full width at half maximum of the dominating emission peak was 68 nm at 1.53 μm. The large stimulated emission cross section of the Er 3+ was calculated by the McCumber theory. The spectroscopic properties of Er 3+ ion were compared with those in different glasses. The full width at half maximum and σ e are larger than those of other glass hosts, indicating this studied glass may be a potentially useful candidate for high-gain erbium-doped fiber amplifier.     

Optical planar waveguides in yb3＋-doped phosphate glasses produced by He＋ ion implantation

Optical planar waveguides in Yb 3+-doped phosphate glasses are fabricated by implanting triple-energy helium ions. The guiding modes and the near-field intensity distribution are measured by using the prism-coupling method and the end-face coupling setup with a He-Ne laser at 633 nm The intensity calculation method (ICM) is used to reconstruct the refractive index profile of the waveguide. The absorption and the fluorescence investigations reveal that the glass bulk features are well preserved in the active volumes of the waveguides, suggesting the fabricated structures for possible applications as waveguide lasers.     

Enhancement of up-conversion Yb3＋/Tm3＋/Er3＋ tri-doped tellurite glass luminescence properties in transparent oxyfluoride ceramics

Optically transparent Er3＋/Tm3＋/Yb3＋ tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO2-15ZnO-7ZnF2-3YF3-1.5YbF3-0.3ErF3-0.2TmF3 （mol%） is prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nano-crystals in glass matrix appear to be smaller than 100 nm from the scanning electron mi- croscope measurement. Visible up-conversion luminescence of the as melted glass and glass ceramics is investigated. The three-color up-conversion luminescence intensities by 980-nm pumping are increased significantly due to the heat treatment, and the blue intensity increases with a higher magnitude than other wavelengths after heat treatment.