Excited States Of Er3 Research Articles

Boosting near-infrared photoluminescence efficiency of erbium ions and ZnO quantum dots codoped amorphous silica thin films

Er3+ ions and ZnO QDs codoped amorphous silica thin films are prepared by the modified sol-gel spin-coating technique. By introducing the ZnO QDs as sensitizers, the PL emission intensity of Er3+ ions is enhanced by more than two orders of magnitude. With the increasing annealing temperature, the lengthening PL emission lifetime indicates the gradual passivation of the non-radiative trap states. The thermal quenching behavior of PL emission intensity is analyzed by the temperature-dependent PL spectra. With the increasing annealing temperature, the decrease of activation energy suggests the narrowing of energy level difference between the excited state of Er3+ ions and the defect state of ZnO QDs. The gradually improved phonon-assisted energy transfer efficiency results in the greatly enhanced PL efficiency of Er3+ ions. These results will be a starting point for further research on the sensitization mechanisms in the rare earth ions and wide-bandgap QDs codoped amorphous silica.

Photoluminescence properties of Er3+ and Eu3+ ions based on oxide host for optical temperature sensing with high sensitivity

Motivated from increasing demands of non-contact optical temperature sensing, the Yb3+-Er3+ and Eu3+ doped NaY9Si6O26 (NYS) oxide phosphors were designed by high-temperature solid-state reaction method. The phase purity of the as-prepared samples was checked from XRD patterns. For the upconversion luminescence in NYS:Yb3+,Er3+, the optimal Er3+ doping content was determined to be 1 mol%, and the characteristic emission peaks of Er3+ were observed in the region of 500–700 nm. In Eu3+ activated NYS phosphors, it has been found that the emissions originating in 5D1 and 5D0 levels demonstrate different change tendencies in intensity with Eu3+ doping concentration. By studying the temperature-dependent luminescent spectra, it was indicated that the emissions intensities from different excited states of Er3+ change differently with temperature. Two kinds of fluorescence intensity ratio (FIR) strategies were used in NYS:10%Yb3+,1%Er3+, containing thermally-coupled levels and non-thermally-coupled levels. In the NYS:3%Eu3+ phosphor, it was found that the FIR for 577 and 536 nm emissions follows a linear relation with temperature. The high sensitivities in the present phosphors indicate the potential application in optical temperature sensing.

Enhanced luminescence through interface energy transfer in hierarchical heterogeneous nanocomposites and application in white LEDs

Highly efficient light-emitting materials are essential for achieving high-performance devices. Here, a novel composite system, as well as enhanced luminescence processes, was designed, where NaLn(MoO4)2 ultra-small nucleus can be effectively isolated by In(OH)3 to form NaLn(MoO4)2@In(OH)3 composite nanoclusters due to the different nucleation rate between NaLn(MoO4)2 and In(OH)3, and then these small composite clusters gradually self-assemble into hierarchical structures. As we expected, the enhanced luminescence was achieved from hierarchical NaLn(MoO4)2 nanostructures with adjusting the distance among NaLn(MoO4)2 ultra-small nucleus by inserting In(OH)3. A series of spectroscopy results show that the In(OH)3 not only acts as an energy transfer bridge from CTB Eu3+ → O2− (or MoO42− absorption) to Eu3+, but also can effectively alleviate the concentration quenching of Ln3+ and change the J-O parameters. The Raman peak at 134 cm−1 is helpful to populate the 5D0 level of Eu3+ or the excited states of Er3+, resulting in stronger up/down-conversion emissions. The use of NaLn(MoO4)2@In(OH)3 in white light-emitting diodes (LEDs) has been demonstrated. The combination of red emission from NaLn(MoO4)2@In(OH)3 with blue, green, and yellow emission from halide perovskites could achieve white light with excellent vision performance (an LER of 376 lm/W) and superior color quality (CRI > 92). The findings of this experiment provide a new idea for the design of composite interface materials.

Polarization-resolved Er emission in Er doped GaN bulk crystals

Erbium-doped GaN (Er:GaN) quasi-bulk crystals are emerging as a promising novel gain medium for high energy lasers emitting at the retina-safe wavelength window of 1.5 μm. We report the polarization-resolved photoluminescence (PL) emission spectroscopy studies, which revealed that the pumping efficiency with the excitation polarization parallel to the c-axis of GaN (E⇀||c⇀) is significantly higher than that with the excitation polarization perpendicular to the c-axis of GaN (E⇀⊥c⇀). This phenomenon is a direct consequence of the inherent polar wurtzite GaN lattice, giving rise to a net local field, surrounding each Er ion, along the c-axis of GaN. The temperature dependent behaviors of the PL emission spectra were explained in terms of the Boltzmann population distributions among sublevels within the 4I15/2 ground state and the 4I13/2 first excited state of Er3+ in GaN, thereby providing an improved understanding regarding the origin of the dominant emission lines observed near 1.5 μm. The results suggested that the polarization field in GaN can be exploited to enhance the effective Er excitation cross section by manipulating the polarization of the excitation light source.

Influence of BaX2 (X = Cl, F) and Er2O3 concentration on the physical and optical properties of barium borate glasses

Er3+ ions doped oxyhalide barium borate glasses were prepared by means of conventional melt quenching technique. In the studied glass system, besides the Er3+ doping, barium oxide was partially replaced by BaF2 and/or BaCl2. The amorphous nature of as-prepared glasses was confirmed by X-ray diffraction patterns. The effects of the compositional changes were investigated through spectroscopic techniques such as optical absorption, emission and decay lifetime. It was found that the luminescence and decay lifetime of Er3+: 4I13/2 → 4I15/2 transition are affected by both Er3+ doping and halide insertions. By applying the Judd-Ofelt (JO) theory, the JO intensity parameters (Ωt, t = 2, 4, and 6) were calculated, and the trend Ω2 > Ω4 > Ω6 was found, which is in accordance with previous studies. Optical properties such as electric and magnetic dipole transition probabilities, fluorescence branching ratios, integrated emission cross sections and radiative lifetimes were also obtained and discussed for many excited states of Er3+ ions. The lifetime of the 4I13/2 excited level was measured and compared with the calculated one.

Synthesis of orthorhombic K2YF5: Yb3+, Er3+/Tm3+ nanocrystals and highly efficient multicolor up-conversion luminescence

In our work, the orthorhombic K2YF5 nanocrystals were successfully synthesized via solvothermal method in a mixture of oleic acid and 1-Hexanol. The up-conversion (UC) luminescent properties of orthorhombic K2YF5:Yb3+, Er3+/Tm3+ nanoparticles (NPs) were studied, and the multicolor output, including green, yellow-green, yellow, pink, and blue, was achieved by adjusting the concentrations of Yb3+ sensitizer ion and kinds of activator ions. Meanwhile, the optimal doping concentrations of Yb3+, Er3+/Tm3+ which is a condition that green or blue emissions intensity can reach a maximum were found under 980 nm laser diode (LD) excitation. Furthermore, the fluorescence lifetimes of 4S3/2 excited state of Er3+ and 1G4 excited state of Tm3+ in the K2YF5:Yb3+, Er3+/Tm3+ were tested, which showed that the fluorescence lifetime can reach 1.14 ms and 0.57 ms at the optimal doping concentrations of Yb3+/Er3+ (30%/3%) and Yb3+/Tm3+ (25%/0.2%) respectively, indicating that the K2YF5 nanomaterial owns extremely strong UC emission intensity and long fluorescence lifetime. Indubitably, the outstanding optical properties will make K2YF5 NPs have potential applications in the fields of 3D displays, optical communications, phosphors, and so on.

Thermal stability and luminescence features of phosphate glasses containing K2TeO3 as promising laser materials

In this paper an attempt was made to investigate the compositional, microstructural, thermal and optical properties of 40P2O5- 30ZnO- 20BaF2- 3.8K2TeO3- 1.2Al2O3- 5Nb2O5- 30,000 ppm Er2O3 (PZBKTANEr) novel glasses fabricated by the melt quench technique. The amorphous nature of the glasses was confirmed by X-ray diffraction studies. We estimated the glass transition temperature and thermal stability against the crystallization of present glasses by using differential thermal analysis (DTA). The results of the differential thermal analysis (DTA) indicate that (PZBKTANEr) glasses have a high thermal stability and low tendency to crystallization.The optical absorption edge has been evaluated within the Urbach approach by using UV–vis-NIR spectroscopy. Moreover, the Judd– Ofelt parameters Ω2, Ω4 and Ω6 the oscillator strength type transition probabilities, spectroscopic quality factors, branching ratios and radiative lifetimes of several excited states of Er3+ have been evaluated. The classical Mc Cumber theory was used to evaluate the emission cross-sections for the 4I15/2 → 4I13/2 transition at a wavelength of around 1.54 μm. Gain cross-section for the Er3+ laser transition 4I15/2 → 4I13/2 was obtained. The effective emission cross section bandwidth FWHM (75.924 nm) and height stimulated emission cross-section (5.5 × 10−21 cm−2) of present glasses were reported. Hence the thermal and spectroscopic properties indicate that this glass doped with Er3+ can be used for application of the optical device. Furthermore the structure of this glass was analyzed by Raman spectroscopy.

Effect of sintering temperature on the structural and luminescence properties of Er doped PbWO4 microcrystals

Erbium-doped lead tungstate (PbWO4) microcrystals with different doping concentrations have been synthesized using an aqueous precipitation method under the assistance of cetyltrimethyl ammonium bromide (CTAB). The results characterized by X-ray diffraction and scanning electron microscope show that the tetragonal stolzite microcrystals with a spindle-like shape form flower-like and fork-like microstructures. The band gap was widened due to the structural relaxation after sintering at 873 K. The analysis of Fourier transform infrared transmittance spectra and photoluminescence spectra shows that the excited states of Er3+ ions could be de-excited by the quenching effect from OH and CH2 groups and energy transfer to the defects in the as-obtained samples. The Er3+ ions in the PbWO4 host could be activated via releasing the OH group and the decomposition of the CTAB on the surface of the microcrystal. When the sintered samples were placed for 5 months the green emission peaks of the active Er3+ ions at 523 nm, 529 nm, 544 nm and 551 nm are merged as two peaks at 532 nm and 554 nm because of line broadening from the further relaxation of the structure and the change of the crystal field in the microcrystals.

Investigation of luminescence parameters of novel glasses with composition TeO2-ZnO-NaF-MoO2-Er2O3 as laser material

Fluoroquaternary glasses within system 70TeO2-10ZnO-10NaF-(10 − x)MoO2-xEr2O3 doped with different concentration of xEr2O3 ions were prepared by using melt- quenching technique. The amorphous nature of the glasses confirmed by using X-ray diffraction. Physical parameters viz.: density (ρ), molar volumes (Vm), refractive index (n), an optical energy gap (Eg) and Urbach energy (ΔE) values of prepared glasses were evaluated. Moreover, the Judd–Ofelt parameters Ω2, Ω4, Ω6, the oscillator strength type transition probabilities, Smeas, Scal, spectroscopic quality factors, X, branching ratio, βR and radiative lifetimes, τR, of several excited states of Er3+ have been computed. The gain cross-section of laser transition level from 4I13/2 → 4I15/2 and stimulated emission cross-section estimated with different concentration of Er2O3 ions in all present glasses. Here the spectroscopic properties indicate that these glasses doped with Er3+ are a promising candidate for optical applications.

Synthesis, structure and optical studies of ZnO:Eu3+,Er3+,Yb3+ thin films: Enhanced up-conversion emission

ZnO:Eu3+/Er3+/Yb3+thin films were deposited on Si (100) substrates using the sol–gel spin coating technique. The effect of Yb3+ concentration on the structure, particle morphology and optical properties of the films was examined. X-ray diffraction data showed that all the thin films crystallized in a hexagonal wurtzite structure of ZnO. The particle morphology and the distribution of atomic and molecular ionic species on the surface were investigated using scanning electron microscopy and time‐of‐flight secondary ion mass spectrometry, respectively. Atomic force microscopy was used to determine the surface roughness and particle sizes. Photoluminescence (PL) properties of the samples were measured using a mono-chromatized xenon lamp (conventional PL) and a 980 nm laser (up converted PL) as excitation sources. The conventional PL consisted of the normal defect emission. Yb3+ co-doping was found to improve the up converted (UC) PL intensity of both the RE3+ (Eu3+ and Er3+) ion emissions. This was ascribed to two possible energy transfer mechanisms from the 2F5/2 level of the Yb3+ ions to both the excited states of Er3+ and Eu3+ ions through Yb3+ → Er3+ & Er3+ → Eu3+ and Yb3+ → Eu3+ & Yb3+ → Er3+ on an individual behavior. The mechanism of energy transfer from Yb3+ to Eu3+ is explained by simplified energy level diagrams. The diagrams illustrate various defect levels and f-f transitions of the dopant ions. The emission colour was quantified by the standard international commission on illumination (CIE) chromaticity diagram.

Enhancement of spectroscopic and luminescence properties of Er3+ doped tellurite glasses by adding P2O5 for lasing materials

Er3+-doped phosphor-tellurite glasses has been synthesized by conventional melting method. Results of differential scanning calorimetry (DSC) measurements indicate a good thermal stability of tellurite glasses. The DSC measurements show an improvement of thermal stability of glass hosts after adding P2O5. The structures of glasses were investigated by X-ray diffraction (XRD) and Raman spectroscopy to understand their dependence of structure on composition. Absorption spectrum from near infrared to visible was obtained and the Judd–Ofelt (J-O) intensity parameters (Ω2, Ω4, and Ω6) were determined. Spontaneous emission probabilities of some relevant transitions, branching ratio, and radiative lifetimes of several excited states of Er3+ have been predicted using intensity J-O parameters. Up-conversion luminescence characteristics, under 977 nm excitation wavelength, have been investigated at room and low temperature in these glasses. Intense green and red emissions from Er3+ centered at 534 nm, 548 nm and 660 nm, corresponding to the transitions 2H11/2→4I15/2, 4S3/2→4I15/2 and 4F9/2→4I15/2, respectively, were simultaneously observed. The quadratic dependence of the up-conversion emission on the excitation power indicates that two-photon steps are involved for the three visible emission bands. The PL lifetimes is found to decrease in the temperature range 77–300K. Using the Mc-Cumber method, emission cross-section (σe), Absorption cross-section (σa), and gain cross-section (G(λ)) for the 4I13/2→4I15/2 transition, were calculated. By analyzing obtained data based to all advantages after adding P2O5, the tellurite glasses can be used as potential host material for developing optical amplifiers applied for 1.53 µm band broad and high-gain erbium-doped fiber amplifiers (EDFA).

Spectroscopic and pump power dependent upconversion studies of Er3+-doped lead phosphate glasses for photonic applications

Er3+-doped lead phosphate glasses (PKAPbNEr) were prepared by a melt quenching technique and their spectroscopic properties were investigated for 1.54 μm fiber amplifier applications. Judd-Ofelt (JO) analysis was carried out from the absorption spectra of 1.0 mol% Er2O3-doped glass and the derived JO parameters were found to be Ω2 = 4.7, Ω4 = 0.7 and Ω6 = 1.2 (×10−20 cm2). The transition probabilities, branching ratios and radiative lifetimes for several excited states of Er3+ were predicted using JO parameters and refractive index. The stimulated emission-cross section of the green emission (4S3/2 → 4I15/2) has been determined to be 3.31 × 10−21 cm2. Absorption cross-section (σabs(λ)), emission cross-section (σemi(λ)) and gain bandwidth (FWHM × σemi(λ)) of 4I13/2 → 4I15/2 transition at 1.54 μm were deduced from the McCumber theory and found to be 4.97 × 10−21, 6.63 × 10−21 and 267 × 10−28 (cm2), respectively. The decay curves exhibit single exponential nature and the lifetimes were determined to be 4.50, 4.57, 2.61, 2.06, 1.48 and 1.04 ms for 0.05, 0.1, 0.5, 1.0, 2.0 and 4.0 mol %, respectively, for Er2O3-doped lead phosphate glasses. The results confirm that the present Er3+-doped lead phosphate glasses could be considered as promising candidates as gain media for photonic applications.

The Temperature-Dependence of Multiphonon Relaxation of Rare-Earth Ions in Solid-State Hosts.

Rare-earth ions are used in a wide range of emissive devices - ranging from lasers to displays - where high optical efficiency and narrow-linewidth are important. While their radiative properties are important, nonradiative properties are also critical since they can reduce optical efficiency and generate heat. In this paper, theories for multiphonon relaxation rate are reviewed for rare-earth excited states in solid-state dielectric hosts. A range of various approaches are used to simplify the mathematical form of the rate equations. The 2H9/2 excited state of Er3+, responsible for a technologically significant green emission, is modeled to show how the various theories manifest an order-of-magnitude variation in the thermal dependence of the multiphonon relaxation rate, as well as anomalous local minima in phonon scattering for temperatures above 0 K. This work proposes a corrective term of two quanta (Δν= + 2) of the mediating phonon energy to energy gap, so the calculated and the experimentally determined relaxation rates are equal. Radiative quantum efficiencies of both the 1G4→3H5 ~1.3 μm and 3F3→3F2 ~7 μm of Pr3+ are calculated to show the importance of both proper measurement of phonon energy and application of the multiphonon relaxation rate theory.

Absorption spectra of bulk aluminum nitride crystals doped with Er3+ ions

This Letter presents results of analysis of the absorption spectra of AlN:Er3+ bulk crystals. In the spectral of 370–700 nm, absorption lines responsible for intraconfiguration electron transition from the ground state 4I15/2 to the excited states of Er3+ ions are found. Transitions to the levels of the 4F9/2, 2H11/2, and 4G11/2 states at 2 K are studied in detail. The number of observed lines for these transitions fully agrees with that theoretically possible for f–f electron transitions in Er3+ ions found in a noncubic crystal field. The small width of the observed lines and their number indicate that erbium ions displace mostly one regular crystal position. Most probably, Er3+ occupies the position of Al. Energy positions of excited states for the considered transitions are determined.

Disputed Mechanism for NIR-to-Red Upconversion Luminescence in NaYF4:Yb(3+),Er(3+).

The most commonly proposed mechanisms for NIR-to-red upconversion in the well-studied material β-NaYF4:Er(3+),Yb(3+) are evaluated in order to resolve inconsistencies that persist in the literature. Each of four possible mechanisms is evaluated in terms of the direct analysis of spectroscopic data. It is shown that there are no important mechanisms that involve the first excited state of Er(3+), (4)I13/2, as an intermediate state. A large body of evidence overwhelmingly supports the proposed mechanism of Anderson et al., which suggests an intimate connection between NIR-to-red and NIR-to-blue upconversion. Namely, both red and blue upconversion are produced primarily by a three-photon excitation process that proceeds through the green emitting state to a dense manifold of states, (4)G/(2)K, above the blue emitting state, (2)H9/2. Competing relaxation mechanisms out of (4)G/(2)K determine the relative amounts of blue and red upconversion produced. Multiphonon relaxation from (4)G/(2)K results in blue upconversion, whereas back energy transfer from Er(3+)((4)G/(2)K) to Yb(3+)((2)F7/2) results in red emission.

Influence of Fe3O4 nanoparticles on structural, optical and magnetic properties of erbium doped zinc phosphate glass

Tunable modifications of physical and optical properties of metallic nanoparticles (NPs) embedded rare earth (RE) doped inorganic binary glasses are the key issue. Series of glass with composition (69-x)P2O5–30ZnO–1Er2O3–(x)Fe3O4, where 0 ≤ x ≤ 2 mol% containing Fe3O4 NPs are prepared by melt quenching method and characterized using XRD, UV–Vis–NIR, PL, TEM and vibrating sample magnetometer (VSM) techniques. The Fe3O4 NPs concentration dependent density, molar volume, structural, magnetic and optical properties are determined. The XRD pattern confirms the amorphous nature of all samples. The glass density is found increase and molar volume decrease with the increase of NPs concentration. The TEM micrographs reveal the presence of spherical NPs of average diameter ∼26 nm with homogenous distribution. The UV–Vis–NIR absorption spectra exhibit ten absorption bands centered at 376, 406, 448, 486, 522, 546, 652, 798, 976 and 1534 nm corresponding to the absorption from 4I15/2 ground state to various excited states of Er3+ ions. The optical band gap energy for direct (4.47–3.64 eV) and indirect (4.27–3.53 eV) transitions and Urbach energy (0.65–0.15 eV) are found to decrease with the increase of Fe3O4 contents. The decrease in band gap energy is ascribed to the creation of non bridging oxygen (NBO) ions in the glass network. The emission spectra at 478 nm excitations display two prominent peaks centered at 532 and 634 nm originate from 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively. Furthermore, increasing NPs concentration dependent luminescence quenching is attributed to the energy transfer from the erbium ion to NPs. These glasses displaying ferrimagnetic behavior in the concentration range of 1.5–2 mol% of NPs verify the presence of iron oxide or ferrite in the glass sample are useful for magneto-optic devices.

Step-like increase of quantum yield of 1.5 μm Er-related emission in SiO2 doped with Si nanocrystals

We investigate the excitation dependence of the efficiency of the Si nanocrystals-mediated photoluminescence from Er3+ ions embedded in a SiO2 matrix. We show that the quantum yield of this emission increases in a step-like manner with excitation energy. The subsequent thresholds of this characteristic dependence are approximately given by the sum of the Si nanocrystals bandgap energy and multiples of 0.8 eV, corresponding to the energy of the first excited state of Er3+ ions. By comparing differently prepared materials, we explicitly demonstrate that the actual values of the threshold energies and the rate of the observed increase of the external quantum yield depend on sample characteristics—the size, the optical activity and the concentration of Si nanocrystals as well Er3+ ions to Si nanocrystals concentration ratio. In that way, detailed insights into the efficient excitation of Er3+ ions are obtained. In particular, the essential role of the hot-carrier-mediated Er excitation route is established, with a possible application perspective for highly efficient future-generation photovoltaics.

Spectroscopic and luminescence characteristics of erbium doped TNZL glass for lasing materials

Rare earth-doped tellurite glasses are very attractive materials for laser and photonic applications, such as optical amplifiers. They have a good glass stability which leads to an enhancement of the radiative transition. In the present study, a new transparent bulk glass with the composition 85TeO2–5Nb2O5–5ZnO–5LiF doped with 1% Er2O3 (TNZL doped with Er3+) was prepared by using the conventional melt-quenching method. The thermal stability and the crystallization behavior of the glass were investigated using Differential Scanning Calorimetry (DSC), X-ray diffraction and Raman spectroscopy. Furthermore, UV–vis–NIR spectra were determined. From these Judd–Ofelt parameters, Ωk (k=2, 4, 6) of Er3+ were evaluated. The oscillator strength type transition probabilities, spectroscopic quality factors, branching ratio and radiative lifetimes of several excited states of Er3+ were predicted using intensity Judd–Ofelt parameters. The down conversion, up conversion and near infrared luminescence of the Er3+ ions in TNZL glass were investigated. Green and red emissions corresponding to (2H11/2, 4S3/2)→4I15/2 and 4F9/2→4I15/2 transitions were observed.

Optical characterization, infrared emission and visible up-conversion in Er3 + doped tellurite glasses

In this work, Er3+ doped tellurite glasses have been prepared with the composition (82.5-x) TeO2+4.5Bi2O3+11.5ZnO+1.5Nb2O5+x Er2O3 (x=0.1, 0.3, 0.5, 0.7, 1.0mol%) by melt-quenching method and their physical, spectroscopic properties were investigated. The experimental oscillator strengths (fexp) of individual absorption peaks are used to estimate the Judd–Ofelt intensity parameters (Ωλ, λ=2, 4, 6). Judd–Ofelt intensity parameters are used to calculate the spontaneous transition probabilities, radiative lifetimes and branching ratios for certain excited states of Er3+ ions. NIR emission and visible up-conversion luminescence were observed at room temperature for all glasses by exciting with 980nm laser radiation. The emission characteristics such as peak stimulated emission cross section, FWHM, figure of merit, optical gain cross sections and measured lifetimes have been obtained for the observed Er3+: 4I13/2→4I15/2 transition in the above glass composition for all the concentrations and are compared with that of the reported. Finally, NIR to visible energy conversion has been analyzed for all glasses excited at 980nm and suitable mechanism was proposed.

Er–Yb codoped phosphate glasses with improved gain characteristics for an efficient 1.55 µm broadband optical amplifiers

We have investigated the optical properties of phosphate glasses codoped with Er3+–Yb3+ as a function of Yb3+concentration in order to evaluate their potential as both glass laser systems and amplifier materials. The results of differential scanning calorimetry (DSC) measurements indicate a good thermal stability of phosphate glasses. The Judd–Ofelt (JO) model has been applied to absorption intensities of Er3+ (4f11) transitions to establish the so-called Judd–Ofelt intensity parameters: Ω2, Ω4,Ω6. With the weak spectroscopic quality factors Ω4/Ω6 (0.38), we expect a relatively prominent Infrared laser emission. The intensity parameters are used to determine the spontaneous emission probabilities of some relevant transitions, the branching ratio and the radiative lifetimes of several excited states of Er3+ and compared to the equivalent parameters for other host glasses.Both the IR photoluminescence (PL) intensity and the PL decay time were found to largely increase with Yb3+concentration and the maximum quantum efficiency for the 1.55µm emission was found to be in the order of 91%. We show that the Yb3+ acts as sensitizer for Er3+ and contributes largely to the improvement of the spectroscopic properties of phosphate glasses codoped with Er3+–Yb3+.Using McCumber method, absorption cross-section and calculated emission cross-section, for the 4I13/2→ 4I15/2 transition, were determined and compared for the doped and codoped glasses. The phosphate glasses are promising gain media for developing the solid-state 1.55µm optical amplifiers.