Spectroscopic properties of Er 3 þ ions in multicomponent tellurite glasses (original) (raw)
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Radiative and non radiative spectroscopic properties of Er 3+ ion in tellurite glass
Optics Communications, 2006
We have investigated in detail the mechanism of infrared emission and upconversion emission of Er 3+ in tellurite glass as a function of the dopant concentration. Both the infrared and upconversion emissions are competing processes and the efficiency of infrared emission at 1534 nm is 100% at the lowest Er content (0.5 mol%) and reduces to 50% at higher dopant concentration (>2 mol%). The green upconversion emission at 548 nm is mainly due to the excited state absorption (ESA) from 4 I 11/2 , which populate the 4 F 7/2 level. In addition to this, the possible energy transfer (ET) through Er 3+ ( 4 I 11/2 ) + Er 3+ ( 4 I 11/2 ) ! Er 3+ ( 4 F 7/2 ) + Er 3+ ( 4 I 15/2 ) can also results in the green emission as is noticed from the concentration dependent efficiency change of the green emission. The fluorescence quenching of green emission with Er concentration may be related with the cross relaxation (CR) process 2 H 11/2 + 4 I 15/2 ! 4 I 9/2 + 4 I 13/2 . The red emission is due to the combined effect of the ESA from level 4 I 13/2 to 4 F 9/2 , the energy transfer process described by Er 3+ ( 4 I 13/2 ) + Er 3+ ( 4 I 11/2 ) ! Er 3+ ( 4 F 9/2 ) + Er 3+ ( 4 I 15/2 ) and the cross relaxation process.
Study of luminescence properties of Er3+-ions in new tellurite glasses
Optical Materials, 2004
The effects of concentration of Er 3þ ions in tellurite glasses on the decay time, spectral width and weighted spectral peak are studied. A broad emission spectrum of width 121 nm peaked at wavelength of 1.5 lm is obtained in 2.5 mol% Er doped glasses. The maximum decay time of 4 I 13=2 fi 4 I 15=2 transition (at wavelength 1.5 lm) is about 4.5 ms for 1.0 mol% Er doped glasses. Strong green and red upconversion emission at emission 550 nm ( 4 S 3=2 fi 4 I 15=2 ) and 670 nm ( 4 F 9=2 fi 4 I 15=2 ) are observed from Er 3þ -doped tellurite glasses upon continuous wave excitation at 975 nm. It is found that the upconversion efficiency goes up with the increasing concentration of the Er 3þ ions.
Journal of Solid State Chemistry, 2003
Red, green, and blue emission through frequency upconversion and energy-transfer processes in tellurite glasses doped with Tm 3+ and Er 3+ excited at 1.064 mm is investigated. The Tm 3+ /Er 3+ -codoped samples produced intense upconversion emission signals at around 480, 530, 550 and 660 nm. The 480 nm blue emission was originated from the 1 G 4 -3 H 6 transition of the Tm 3+ ions excited by a multiphoton stepwise phonon-assisted excited-state absorption process. The 530, 550 nm green and 660 nm red upconversion luminescences were identified as originating from the 2 H 11/2 , 4 S 3/2 -4 I 15/2 and 4 F 9/2 -4 I 15/2 transitions of the Er 3+ ions, respectively, populated via efficient cross-relaxation processes and excited-state absorption. White light generation employing a single infrared excitation source is also examined. r
Journal of Non-Crystalline Solids, 2007
Absorption, emission, excitation spectra and the lifetime of the 4 S 3/2 excited luminescent state of Er 3+ ions in a fluorine containing (lead, lanthanum)-tellurite glass have been studied. The glass exhibits a strong green luminescence upon excitation through 380 nm (4 I 15/2 ! 4 G 11/2) absorption band of its Er 3+ ions. The spectrum consists of a strong green component in the wavelength range 534-553 nm due to luminescence transitions 2 H 11/2 ! 4 I 15/2 and 4 S 3/2 ! 4 I 15/2 and a very weak red component in the range 650-710 nm due to 4 F 9/2 ! 4 I 15/2 transition. The Stark split components of the 4 S 3/2 state are not very clear in the spectrum, but the biexponential luminescence decay of the 4 S 3/2 state confirms the presence of the Stark levels. A rapid conversion of the upper Stark level to the lower level is also evident from the decay kinetics which helps greater number of ions to populate in the lower stark level of the 4 S 3/2 state. Thus, the present study indicates that the glass may be a suitable candidate for use as a laser medium in making a solid state green laser by pumping the later by normal route.
Journal of Alloys and Compounds, 2018
Efficient up-converted lasing materials are required for high performing, durable and low cost photonic devices. Rare earth ions doped glass systems with modified optical properties may meet this need. In this view, erbium (Er 3+) ions doped zinc-magnesiumtellurite glass system of composition (75-x)TeO 2-15ZnO-10MgO-xEr 2 O 3 (0.5 ≤ x ≤ 2.0 mol%) was prepared via melt-quenching method. Optical behavior of such glasses was determined as a function of changing Er 2 O 3 content to examine the feasibility of achieving up-converted lasing media. Judd-Ofelt (J-O) intensity (Ω 2 , Ω 4 , Ω 6) and radiative parameters were evaluated. Glass hardness was increased linearly with increasing Er 3+ ions concentration. The emission spectra revealed three peaks around 470 nm, 500 nm and 550 nm. Effect of Er 2 O 3 content on the 4 I 13/2 → 4 I 15/2 transition was quantified in terms of fluorescence intensity and lifetime. The width of the near-infrared fluorescence band (1.53 µm) was broadened from 58.77 to 60.01 nm with the increase of Er 2 O 3 content from 0.5 and 2.0 mol%. The proposed glass compositions were demonstrated to be potential for solid-state lasers, near infrared sensors, and other optical devices.
Journal of Applied Physics, 2007
An in-depth spectroscopic study is performed on Er 3+ ͑4f 11 ͒ ions doped into a fluorine containing ͑lead, lanthanum͒-tellurite glass host, containing nominal 1.93 at. % of Er 3+ . The standard Judd-Ofelt ͑JO͒ model is applied to the room temperature absorption intensities of Er 3+ ͑4f 11 ͒ transitions in the tellurite glass host to obtain three phenomenological intensity parameters, ⍀ 2 , ⍀ 4 , and ⍀ 6 . These parameters are subsequently used to determine the radiative decay rates, radiative lifetimes, and branching ratios of the Er 3+ transitions from the upper multiplet manifolds to the corresponding lower-lying multiplet manifolds 2S+1 L J of Er 3+ ͑4f 11 ͒ in the tellurite glass host. The emission cross sections of the intermanifold Er 3+ 4 I 13/2 → 4 I 15/2 ͑1.5 m͒ and 4 S 3/2 → 4 I 15/2 ͑540 nm͒ transitions have been determined. The room temperature fluorescence lifetimes of the 4 I 13/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transitions in this tellurite glass host were also measured. From the radiative lifetime determined from the JO model and measured fluorescence lifetime, the quantum efficiency of this material was also determined. The spectroscopic properties were compared with those of Er 3+ ͑4f 11 ͒ in other halotellurite glass hosts. We also analyzed the band structure observed in the absorption spectra of Er 3+ in the tellurite glass at 8 K. The structure can be interpreted in terms of the ligand-field splitting of the energy levels of the Er 3+ ion in the local environment established by the glass matrix into which Er 2 O 3 has been introduced. The spectroscopic analysis of Er 3+ ͑4f 11 ͒ suggests that the tellurite glass is an excellent candidate for various photonic applications.
Optical Materials, 2003
Optical transitions of Er 3þ ion in two tellurite glasses of molar composition 75TeO 2 :12ZnO:10Na 2 O:2PbO:1Er 2 O 3 and 75TeO 2 :12ZnO:10Na 2 O:2GeO 2 :1Er 2 O 3 were investigated. The measured absorption and emission spectra were analysed by Judd-Ofelt and McCumber theories, in order to obtain radiative transition rates and stimulated emission cross sections. It was found that these glasses have high and broadband absorption and stimulated emission cross sections at 1.5 lm. For the metastable 4 I 13=2 level, by comparing the measured lifetime with the calculated radiative decay time, quantum efficiency higher than 80% was found. (R. Rolli). 0925-3467/03/$ -see front matter Ó 2002 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 5 -3 4 6 7 ( 0 2 ) 0 0 0 9 2 -7
Optical properties of Er 3+ ions in transparent glass ceramics
Journal of Alloys and Compounds, 2001
A study of optical properties and upconversion processes among Er ions in oxyfluoride glass and glass ceramic matrix has been carried out. From optical absorption spectra, the oscillator strengths have been obtained for several transitions and they have been used to calculate the Judd-Ofelt parameters. Experimental lifetime values are compared with those obtained with the Judd-Ofelt theory. Different 31 upconversion emissions at 545, 660 and 800 nm have been obtained in Er doped glass and glass ceramics by exciting at 975 nm. A systematic investigation of the green upconversion is reported with the purpose of determining the involved upconversion mechanisms.
Structural and luminescence behavior of Er3+ ions doped Barium tellurofluoroborate glasses
Er3+ doped Barium tellurofluoroborate glasses (BTFBxE) with the chemical composition (30 x)TeO2 + 30B2O3 + 20BaO + 20BaF + xEr2O3 (where x = 0.01, 0.05, 0.1, 0.5, 1.0 and 2.0 in wt%) were prepared following the melt quenching technique. The different vibrational modes of borates and tellurites in the prepared glasses were explored through FTIR and Raman spectra. The optical absorption spectra have been used to determine the ionic/covalent nature of the metal–ligand bond in the prepared glasses with the help of Nephelauxetic ratio (b) and bonding parameter (d) studies. The optical band gap of direct and indirect allowed transitions were determined from Tauc’s plot and the variations of band gap energy with structural arrangements were discussed. The Urbach energy values were determined and the relatively lower values of the Urbach’s energy reveal the minimal degree of disorderness in the prepared glasses. The oscillator strengths (fexp and fcal) and Judd–Ofelt (JO) intensity parameters (X2, X4 and X6) were calculated with the application of JO theory and the trends of the JO intensity parameters are found to be X2 > X6 > X4 for all the prepared glasses with a minimum variation in X2 intensity parameter values. A bright green emission was observed from the 2H11/2 + 4S3/2?4I15/2 transition and the radiative properties such as transition probability (A), stimulated emission cross-section (rEP ), branching ratio (br) and radiative lifetime (s) were calculated using the JO parameters. The suitability of the prepared glasses for the fabrication of photonic devices were also discussed and reported in the present work.
Journal of Non-Crystalline Solids, 2003
A comparison between the radiative lifetimes of the 4 I 13=2 level of Er 3þ derived from the conventional Judd-Ofelt (J-O) method and from a simple formula, that corresponds to Einstein relation for the emission probability of a twolevel system, has been carried out in some typical glasses, such as germanate, phosphate, silicate, and tellurite. The uncertainties of the radiative lifetimes are evaluated using standard error analysis; it comes out that uncertainties are much larger (some tens %) when using the J-O method than with the simple formula (error less than 1%). The same simple method can be used to calculate the radiative lifetimes of other rare earth ions, such as Ho 3þ , Tm 3þ and Yb 3þ .