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1.
Tellurite glasses (TeO2–ZnO–Nb2O5) mono-doped Er3+ and co-doped Er3+/Ce3+ have been prepared using the melt-quenching technique. To evaluate the effect of Ce3+ on the structural, thermal stability of glass hosts and fluorescence properties of Er3+, X-ray diffraction patterns, Ftir spectra, differential scanning calorimeter curves, absorption spectra, fluorescence emission spectra, fluorescence lifetimes, up-conversion emission spectra of glass samples were measured and investigated. Using Judd–Ofelt theory, we calculated intensity parameters (Ω2, Ω4 and Ω6), spontaneous emission probabilities, the radiative lifetime, luminescence branching factors and the quantum yield of luminescence for 4I13/2 → 4I15/2 transition. The co-doping with Ce3+ was effective on the suppression of up-conversion emission of Er3+ owing to the phonon-assisted energy transfer: Er3+:4I11/2 + Ce3+:2F5/2 → Er3+:4I13/2 + Ce3+:2F7/2 which contributed the effective enhancement of 1.53 µm fluorescence emission. The change in optical properties with the addition of Ce3+ ions have been discussed and compared with other glasses. Using the Mc Cumber method for the 4I13/2 → 4I15/2 transition, absorption cross-section, calculated emission cross-section, and gain cross-section values support that TZNEr1Ce1 glass is a potential material for developing broad-band and high-gain erbium-doped fiber amplifiers applied for 1.53 µm.  相似文献   

2.
The Er-doped YAB (YAl3(BO3)4) is a potential self-frequency-doubling laser material. Single crystals were grown by the top-seeded flux method. The absorption spectra of the infrared Er3? transitions were monitored in YAB crystals in the 9–300 K temperature range by high-resolution Fourier transform spectroscopy. In the whole spectral range the energy levels and Stark components of 12 transitions were detectable. In this paper the two infrared transitions (from the 4I15/2 ground state to the 4I13/2 and 4I11/2 levels) were analyzed in detail. The low temperature absorption spectra of Er:YAB consist of sharp lines, the number of which corresponds to the theoretical predictions. This suggests that Er3? ions occupy one specific lattice site (yttrium positions) with negligible aggregation at the higher dopant concentrations investigated (i.e. 0.12 Fr atom/YAB mole).  相似文献   

3.
Polarized spectral properties of Er3+:NaGd(WO4)2 single crystal are reported. The crystal was grown by the Czochralski method. The Judd–Ofelt theory was applied to analyze the polarized absorption spectra and then calculate the spontaneous emission probabilities, radiative lifetimes, and branching ratios. Fluorescence decay curves of the 4 I 13/2, 4 I 11/2, and 4 S 3/2 multiplets for the Er3+ ions were measured. Stimulated emission cross-sections of the 4 I 13/24 I 15/2 transition obtained by the Fuchtbauer–Ladenberg formula and the reciprocity method were compared. Multi-phonon relaxation rates of the crystal were estimated. Green up-conversion fluorescence around 531 and 552 nm was observed, and the possible up-conversion mechanisms were proposed. PACS 78.20.-e; 42.70.Hj  相似文献   

4.
Localized desvitrifiation in strontium barium niobate glass doped with Er3+ under laser irradiation has been carried out. The samples of this study have been fabricated by the melt quenching method and doped with 5% mol of Er3+. A 1.5-W cw Ar laser was focused on the sample to obtain desvitrifiation of the glass. Evidence of the changes induced by the Ar laser has been observed through the analysis of the photoluminescence of the Er3+ ions. The transitions corresponding to 2H11/24I15/2, 4S3/24I15/2 and 4F9/24I15/2 have been studied to analyze structure changes. Microluminescence measurements have been carried out to spatially select positions inside and outside the irradiated area. We have observed changes in the emission bands corresponding to these transitions. The emission bands from Er3+ ions in the irradiated zone show a resolved structure while they are broadened outside that area. These changes in the optical properties of the Er3+ ions indicate that the Ar-laser irradiation has produced a change in the local structure of the material. These results show that a localized desvitrifiation has been produced after the laser action and the transition from glass to glass ceramic has been completed.  相似文献   

5.
The absorption and luminescence spectra of neodymium in a binary inorganic solvent—phosphorus oxychloride-antimony pentachloride—are measured. The spectra are analyzed in terms of the Judd-Ofelt theory. The Judd-Ofelt parameters Ωλ, the oscillator strengths of the main absorption bands, the spontaneous emission probabilities, the radiative lifetime, the luminescence quantum yields, and the stimulated emission cross sections for the 4 F 3/24 I 11/2 laser transition are calculated.  相似文献   

6.
肖凯  杨中民  冯洲明 《物理学报》2007,56(6):3178-3184
研究了Er3+离子掺杂钡镓锗玻璃的吸收光谱、拉曼光谱和上转换光谱.分析了Er3+离子在钡镓锗玻璃中的上转换发光机理.结果表明:玻璃的最大声子能量为828cm-1,紫外截止波长为275nm.采用800nm和980nmLD激发玻璃样品,在室温下观察到强烈的上转换绿光和红光发射.随着Er3+离子浓度的增加,绿光发光强度先增加后减小,而红光发光强度呈单调递增趋势.能量分析表明:800nmLD激发产生的绿光主要源于Er3+离子4I13/2能级的激发态吸收过程;红光发射主要源于Er3+离子4I13/2能级与4I11/2能级之间的能量转移过程.980nmLD激发产生的绿光主要源于Er3+离子4I11/2能级之间的能量转移过程;而红光发射主要源于Er3+离子4I13/2能级与4I11/2能级之间的能量转移过程和4I13/2能级的激发态吸收过程.通过量子效率分析,发现采用800nmLD激发Er3+离子掺杂浓度为1mol% 的样品时,上转换绿光发光效率最高. 关键词: 上转换发光机理 3+离子掺杂')" href="#">Er3+离子掺杂 钡镓锗玻璃  相似文献   

7.
The Er3+-Yb3+ codoped Al2O3 nanoparticles with an average particle size of about 50 nm have been synthesized by an arc discharge synthesis method. The green and red up-conversion emissions centered at about 526, 547 and 677 nm, corresponding respectively to the 2H11/24I15/2, 4S3/24I15/2 and 4F9/24I15/2 transitions of Er3+, were detected by a 978-nm semiconductor laser diode excitation. The Annealing has evident effect on the up-conversion emissions of the samples: The red up-conversion emission is noticeable before annealing; however, the green up-conversion emission becomes predominant after annealing. The mixture of (Er,Yb)3Al5O12 and α-(Al,Er,Yb)2O3 phases is more favorable for green up-conversion emissions due to an enhancement of the ESA (I) of 4I11/2+a photon→4F7/2 and ET (III) of 2F5/2(Yb3+)+4I11/2(Er3+)→2F7/2(Yb3+)+4F7/2(Er3+) processes. The two-photon absorption up-conversion process is involved in the green and red up-conversion emissions. The results have proved that arc discharge synthesis is a new promising preparation technology for optical materials. Supported by National Natural Science Foundation of China (Grant No. 10804015), the Scientific Research Foundation for Doctor of Liaoning Province (Grant No. 20071095), and the Educational Committee Foundation of Liaoning Province (Grant No. 2008123)  相似文献   

8.
This paper reports on the absorption, visible and near-infrared luminescence properties of Nd3+, Er3+, Er3+/2Yb3+, and Tm3+ doped oxyfluoride aluminosilicate glasses. From the measured absorption spectra, Judd-Ofelt (J-O) intensity parameters (Ω2, Ω4 and Ω6) have been calculated for all the studied ions. Decay lifetime curves were measured for the visible emissions of Er3+ (558 nm, green), and Tm3+ (650 and 795 nm), respectively. The near infrared emission spectrum of Nd3+ doped glass has shown full width at half maximum (FWHM) around 45 nm (for the 4F3/24I9/2 transition), 45 nm (for the 4F3/24I11/2 transition), and 60 nm (for the 4F3/24I13/2 transition), respectively, with 800 nm laser diode (LD) excitation. For Er3+, and Er3+/2Yb3+ co-doped glasses, the characteristic near infrared emission bands were spectrally centered at 1532 and 1544 nm, respectively, with 980 nm laser diode excitation, exhibiting full width at half maximum around 50 and 90 nm for the erbium 4I13/24I15/2 transition. The measured maximum decay times of 4I13/24I15/2 transition (at wavelength 1532 and 1544 nm) are about 5.280 and 5.719 ms for 1Er3+ and 1Er3+/2Yb3+ (mol%) co-doped glasses, respectively. The maximum stimulated emission cross sections for 4I13/24I15/2 transition of Er3+ and Er3+/Yb3+ are 10.81×10−21 and 5.723×10-21 cm2. These glasses with better thermal stability, bright visible emissions and broad near-infrared emissions should have potential applications in broadly tunable laser sources, interesting optical luminescent materials and broadband optical amplification at low-loss telecommunication windows.  相似文献   

9.
Nonequivalent Er3+ sites in LiNbO3 crystals have been evidenced by low-temperature optical absorption measurements. The radiative transition rates for the 4 S 3/2, 4 F 9/2, 4 I 9/2, 4 I 11/2, and 4 I 13/2 levels have been evaluated by the Judd-Ofelt method, and the contribution of multiphonon relaxation to the decay of excited states has been estimated. The quantum efficiency of the 4 I 11/2 level has been estimated to be 6% only, thus the excitation of levels lower than 4 S 3/2 is expected to populate efficiently the 4 I 13/2 level.  相似文献   

10.
Single crystals of erbium-doped La3Ga5.5 Ta0.5O14, grown by the Czochralski method, have been investigated using methods of optical spectroscopy. Room-temperature absorption spectra were analysed in the framework of the Judd-Ofelt theory. Radiative transition rates, radiative lifetimes and luminescence branching ratios for luminescent levels of Er3+ have been evaluated and compared to measured luminescence intensities and lifetimes. The laser potential associated with the 4I13/2-4I15/2 transition near 1.55 μm has been assessed. It has been concluded that La3Ga5.5 Ta0.5,O14:Er crystal is an intermediate gain laser material exhibiting strong inhomogeneous broadening of absorption bands, advantageous for optical pumping with laser diodes.  相似文献   

11.
The absorption, luminescence, and excitation spectra of CaF2, SrF2, and BaF2 crystals with EuF3 or YbF3 impurity have been investigated in the range 1–12 eV. In all cases, strong wide absorption bands (denoted as CT1) were observed at energies below the 4f n -4f n ? 15d absorption threshold of impurity ions. Weaker absorption bands (denoted as CT2) with energies 1.5–2 eV lower than those of the CT1 bands have been found in the spectra of CaF2 and SrF2 crystals with EuF3 or YbF3 impurities. The fine structure of the luminescence spectra of CaF2 crystals with EuF3 impurities has been investigated under excitation in the CT bands. Under excitation in the CT1 band, several Eu centers were observed in the following luminescence spectra: C 4v , O h , and R aggregates. Excitation in the CT2 bands revealed luminescence of only C 4v defects.  相似文献   

12.
The nuclear spectroscopic quadrupole moments for the πh9/25/2-, 1/2-[541] and the πh11/29/2-, 9/2-[514] isomeric states in 169Ta have been measured employing the time differential perturbed angular-distribution technique following the nuclear reaction 159Tb(16O, 6nγ)169Ta at beam energy 104 MeV. The ratio of the intrinsic quadrupole moments has been derived as 1.87(13) from the measured quadrupole precession frequencies of the corresponding states. The model-independent analysis of the equilibrium deformation indicates strong prolate- and oblate-driving nature of the 1/2-[541] and 9/2-[514] orbitals in 169,171Ta isotopes, respectively.  相似文献   

13.
The Er3+ -Yb3+ codoped in Li2O content tungsten -tellurite (TWL) transparent glasses are synthesized and measured the absorption, Raman and upconversion luminescence (UPL) spectra. At room temperature intense green emission peak at 560 nm ( 4S3/24I15/2) and red emission peak at 670 nm ( 4F9/24I15/2) of Er3+ observed even at minimum 86 mW pumping power of infrared 980 nm excitation. For structure of the TWL glass, Raman spectrum result revealed that an important role of WO3 in the formation of glass network linkage with Li2O. Under this influence estimated lifetime of the 4I11/2 of Er3+ was 1.89 μs and due to lower phonon energy of the glass produce strong upconversion signal. The effect of Er2O3 concentration on emission intensity result indicated that green emission intensity initially increase in compare to red emission. Under the 980 nm pump power variation measured the relatively increases the red emission to the green emission intensity and analyze the possible upconversion mechanism and process.  相似文献   

14.
Variation-after-projection (VAP) calculations in conjunction with Hartree-Bogoliubov (HB) ansatz have been carried out for A=100−108 molybdenum (Mo) isotopes. In this framework, the yrast spectra with J max π ≥10+, B(E2) transition probabilities, quadrupole (β2) and hexadecapole (β4) deformation parameters, moment of inertia (I) and square of cranking frequency (ω2) for even-even Mo isotopes have been obtained. The results of the calculation give an indication that it is important to include the hexadecapole-hexadecapole component of the two-body interaction for obtaining various nuclear structure quantities in these Mo isotopes.  相似文献   

15.
We measured the absorption and luminescence spectra of Nd3+ ions in an inorganic solvent POCl3-BCl3. The spectra were analyzed in terms of the Judd-Ofelt theory. We calculated the Judd-Ofelt parameters, oscillator strengths, spontaneous emission probabilities, luminescence quantum yield, and the stimulated emission cross section for the laser transition 4 F 3/24 I 11/2 of the neodymium ion in a POCl3-BCl3-Nd3+ solution.  相似文献   

16.
Based on the analysis of the absorption spectra of Er-doped calcium-niobium-gallium garnet (Er:CNGG) crystals according to the Judd-Ofelt theory, the intensity parameters for these crystals are determined to be Θ2 = 3.43 × 10?20 cm2 Θ4 = 1.20 × 10?20 cm2, and Θ6 = 0.58 × 10?20 cm2. The parameters found are compared with the intensity parameters for other laser oxide crystals. Using these intensity parameters, the probabilities of radiative transitions between the energy levels of Er3+ ions in CNGG crystals and the luminescence branching ratios βJJ’ are calculated. From the measured lifetime of the 4 I 11/2 level of Er3+ ions (τ = 626 μs) and the probability of the radiative transition from this level (A = 192 s?1), it is found that about 88% of the excitation energy in the Er:CNGG crystals is nonradiatively transferred from the 4 I 11/2 to the 4 I 13/2 level. It is suggested that an increase in the oscillator strength and in the line strength of the 4 I 15/22 H 11/2 transition of Er3+ in CNGG crystals, as well as an increase in the intensity parameter Θ2 with respect to the corresponding parameters for other garnet crystals are caused by the existence in CNGG crystals of Er3+ centers with the environment symmetry lower than D 2.  相似文献   

17.
The absorption spectra of the Er3+ ions embedded in the AlN matrix have been investigated. The admixture of erbium was introduced in bulk AlN crystals by diffusion. The absorption lines, which are associated with the intraconfigurational electronic ff-transitions from the ground 4 I 15/2-state to the levels of ion Er3+ excited states have been observed in the spectral range of 370–700 nm. The transitions to the state levels 4 F 9/2, 2 H 11/2, 4 F 7/2, 4 F 5/2, 2 H 9/2, and 4 G 11/2 have been investigated in detail at the temperature T = 2 K. The number of the observed lines for these transitions coincides with the theoretically possible one for the electronic ff-transitions in the ions Er3+, which are in the crystal field with the symmetry below cubic. The narrowness of the observed lines and their number convincingly testify the replacement of preferably one regular crystalline position by erbium ions. The implementation of Er3+ in the Al3+ position with the local symmetry C 3v appears the most probable. The energy positions of the levels of excited states for the investigated transitions have been determined. The diagram of the Er3+ ion energy levels in the AlN crystals has been built.  相似文献   

18.
Yb3+/Dy3+ co-doped Al2O3 nanopowders have been prepared by the non-aqueous sol-gel method and their up- conversion photoluminescence spectra are measured under excitation by 980-nm semiconductor laser. The results show that there are comparatively abundant spectra of up-conversion emissions centered at 378, 408, 527 and 543, and 663 nm, corresponding to 4G9/26H13/2, 4G9/26H11/2, 4I15/26H13/2, and 4F9/26H11/2 transitions of Dy3+, respectively. Two-photon and three-photon processes are involved in ultraviolet, violet, green, and red up-conversion emissions. The energy transition between Yb3+ and Dy3+ is discussed.  相似文献   

19.
The method to pump the FBG written into an Er3+-doped optical fiber is proposed to decrease or increase the group velocity of a probing pulse based on the fact that a pump-induced process changes the refractive index and dispersion associated with the 4I15/2-4I13/2 transition in Er3+-doped optical fiber. The system equations are derived. The group velocity modification is numerically demonstrated and discussed with the effects of an optical pump power, fiber Bragg grating length, doping concentration of Er3+ ions, and modulation amplitude of the grating.  相似文献   

20.
The emission spectra and the lifetime of the lasing transition 4I13/24I15/2 in Er3+-doped TeO2-ZnO binary glass have been studied. The investigation includes Raman scattering spectroscopy as well as optical absorption, luminescence, and lifetime measurements techniques. The influence of erbium concentration on the line-shape of this electron transition has been analyzed. It was observed that the increasing of Er3+ ion concentration, in the 0.2-4 mol% range, results in a structural changes and a significant spectral broadening of the 1.53 μm emission band. Reabsorption has been evoked to explain the broadening of the 4I13/24I15/2 emission line. In the paper, is also reported the effect of the erbium content on the emission intensity of the 4I13/24I15/2 transition as well as on the lifetime of the 4I13/2 level. Based on the electrical-dipole interaction theory, the luminescence concentration quenching mechanism by hydroxyl groups is analyzed. The data suggest that <10% of hydroxyl groups are coupled to erbium ions in the zinc tellurite glass network.  相似文献   

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