Effect of composition on the thermal properties and spontaneous emission probabilities of Tm3+-doped TeO2–LiCl glass

2001 ◽  
Vol 16 (5) ◽  
pp. 1381-1388 ◽  
Author(s):  
G. özen ◽  
B. Demirata ◽  
M. L. öveçoğlu
Keyword(s):  
Thermal Properties ◽  
Spontaneous Emission ◽  
Near Infrared ◽  
Transition Probabilities ◽  
Glass Composition ◽  
Ground Level ◽  
Radiative Transition ◽  
Absorption Bands ◽  
Temperature Range ◽  
Absorption Measurements

The effect of composition on the thermal properties and the spontaneous emission probabilities of various 0.5 mol% Tm2O3 containing (1 − x)TeO2 + (x)LiCl glasses were investigated using differential thermal analysis (DTA) and ultraviolet–visible– near-infrared (UV/VIS/NIR) absorption measurements. DTA curves of the samples were obtained in the 23–600 °C temperature range with a heating rate of 10 °C/min. The value of the glass transition temperature Tg and the crystallization temperatureTc were found to vary with the glass composition. Melting was not observed for the glasses containing less than 50 mol% LiCl in this temperature range. However, a melting peak was observed at Tm = 401 °C for the glasses having higher than 50 mol% LiCl, which were also found to be moisture-sensitive. Absorption measurements in the UV/VIS/NIR region were used to determine spontaneous emission probabilities for the 4f−4f transitions of Tm3+ ions. Six absorption bands corresponding to the absorption of the 1G4, 3F2, 3F3, 3F4, 3H5, and 3H4 levels from the 3H6 ground level were observed. An integrated absorption cross section of each band, except that of 3H5 level, was found to vary with the glass composition. The role of the Judd–Ofelt parameters and therefore the effect of the glass composition on the radiative transition probabilities for the metastable levels of Tm3+ ions are discussed in detail.

Effect of The Glass Composition on The Spontaneous Emission Probabilities of Tm3+ in TeO2-ZnO Glass

2004 ◽  
Vol 848 ◽  
Author(s):  
Gönül Özen ◽  
İdris Kabalcı ◽  
John M Collins ◽  
Xuesheng Chen ◽  
Ottavio Forte ◽  
...  
Keyword(s):  
Spontaneous Emission ◽  
Room Temperature ◽  
Glass Composition ◽  
Glass Structure ◽  
Local Environment ◽  
Ground Level ◽  
Infrared Region ◽  
Stimulated Emission ◽  
Luminescence Spectra ◽  
Absorption Measurements

ABSTRACTThis paper reports our findings for the effect of the glass composition on the local environment of the thulium ions in the glass structure and its spontaneous and stimulated emission probabilities in the infrared region at room temperature. Absorption measurements in the UV/VIS/NIR region were used to determine spontaneous emission probabilities for the 4f-4f transitions of the thulium ion. Six bands corresponding to the absorptions of the 1G2, 3F2, 3F3, 3F4, 3H5, 3H4 from the ground level were observed. Integrated absorption cross-section of each band except that of 3H5 level was found to vary with the glass composition. Luminescence spectra of the samples were measured upon 785nm using a diode laser. Two emission bands centered about 1500nm and 1800nm were observed.The effect of the glass composition on the Judd-Ofelt Parameters and therefore on the spontaneous emission probabilities for the metastable levels of thulium ions will be discussed in detail.

Composition Dependence of the Judd-Ofelt Intensity Parameters in TeO2-PbF2: Tm3+ Glasses

2004 ◽  
Vol 829 ◽  
Author(s):  
Idris Kabalci ◽  
Gonul Ozen ◽  
Adnan Kurt ◽  
Alphan Sennaroglu
Keyword(s):  
Cross Sections ◽  
Composition Dependence ◽  
Strong Dependence ◽  
Local Environment ◽  
Ground Level ◽  
Absorption Bands ◽  
Intensity Parameters ◽  
Nir Absorption ◽  
Doped Glasses ◽  
Absorption Measurements

ABSTRACTTm3+ -doped glasses with the composition of (1-x)TeO2-xPbF2, where x=10, 15, 20, 25 mol.% were synthesized and, their thermal and absorption measurements were investigated. All the glasses were transparent. The absorption bands corresponding to the absorption of the 1G4, 3F2, 3F3, 3F4, 3H5, and 3H4 levels from the 3H6 ground level of the Tm3+ ion were observed in the optical UV/VIS/NIR absorption measurements. We calculated the integrated absorption cross sections of each band except that of 3H5 level was found to vary with composition of the PbF2. The absorption measurements were first made to determine the spontaneous emission probabilities of the 4f-4f transitions of the Tm3+ ions. The calculations were made by using the Judd - Ofelt theory. The Ω2 parameter shows the strongest dependence on the host composition and it increases with the increasing PbF2 amount. The values Ω4 increases rather slowly while the value of Ω6 is practically independent of the composition. The strong dependence of the parameter Ω2 indicates that this parameter is related to the structural change and symmetry of the local environment of the Tm3+ ions in this glass.

scholarly journals Population of Excited States of Al10+ in a Plasma by a Time-Dependent Model

1984 ◽  
Vol 86 ◽  
pp. 221-224
Author(s):  
H. Guennou ◽  
A. Sureau
Keyword(s):  
Population Distribution ◽  
Transition Probabilities ◽  
Ground Level ◽  
Radiative Transition ◽  
Time Dependent ◽  
Hartree Fock ◽  
Ion Collisions ◽  
Finite Set ◽  
Dependent Model ◽  
Time Dependent Model

The present model is the time-dependent version of a previous model (Sureau et al. 1983) in which the population distribution was assumed in steady state. A finite set of levels is partitioned in four subsets: the Z-ion ground-level and, contingently, the first near-degenerated levels (subset 1); all the successive excited Z-ion levels up to n=5 (subset 2); a finite number of higher Rydberg levels (because of the limitation of the series in the plasmas) which are assumed in LTE with the Z+l−ion ground-level (subset 3, called the thermal band); and the Z+l ion ground-level (subset 4).The physical processes explicitly considered are the radiative cascades and the transitions between the Z-ion bound levels induced by electron-ion collisions. The radiative-transition probabilities are given by ab-initio calculations using a modified Hartree-Fock method including the spin-orbit interaction (Sureau et al., 1984). The collision rates are derived by the Van Regemorter formula multiplied by an adjustable parameter Fc.

scholarly journals Influence of Temperature on Water and Aqueous Glucose Absorption Spectra in the Near- and Mid-Infrared Regions at Physiologically Relevant Temperatures

2003 ◽  
Vol 57 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Peter Snoer Jensen ◽  
Jimmy Bak ◽  
Stefan Andersson-Engels
Keyword(s):  
Absorption Spectra ◽  
Near Infrared ◽  
Pure Water ◽  
Glucose Absorption ◽  
Diagnostic Methods ◽  
Effect Of Temperature ◽  
Difference Spectra ◽  
Absorption Bands ◽  
Mid Infrared ◽  
Temperature Range

Near- and mid-infrared absorption spectra of pure water and aqueous 1.0 g/dL glucose solutions in the wavenumber range 8000–950 cm−1 were measured in the temperature range 30–42 °C in steps of 2 °C. Measurements were carried out with an FT-IR spectrometer and a variable pathlength transmission cell controlled within 0.02 °C. Pathlengths of 50 μm and 0.4 mm were used in the mid- and near-infrared spectral region, respectively. Difference spectra were used to determine the effect of temperature on the water spectra quantitatively. These spectra were obtained by subtracting the 37 °C water spectrum from the spectra measured at other temperatures. The difference spectra reveal that the effect of temperature is highest in the vicinity of the strong absorption bands, with a number of isosbestic points with no temperature dependence and relatively flat plateaus in between. On the basis of these spectra, prospects for and limitations on data analysis for infrared diagnostic methods are discussed. As an example, the absorptive properties of glucose were studied in the same temperature range in order to determine the effect of temperature on the spectral shape of glucose. The change in water absorption associated with the addition of glucose has also been studied. An estimate of these effects is given and is related to the expected level of infrared signals from glucose in humans.

scholarly journals Sm3+-Doped Molybdenum Gadolinium Borate Glasses for Orange Emission Laser Active Medium

2018 ◽  
Vol 63 (8) ◽  
pp. 721 ◽  
Author(s):  
R. Rajaramakrishna ◽  
Y. Ruangtawee ◽  
J. Kaewkhao
Keyword(s):  
Energy Transfer ◽  
Active Medium ◽  
Near Infrared ◽  
Transition Probabilities ◽  
Stimulated Emission ◽  
Oscillator Strengths ◽  
Color Temperature ◽  
Absorption Bands ◽  
Orange Emission ◽  
Laser Active Medium

Room temperature visible and near infrared optical absorption and emission spectra of Sm3+-doped molybdenum gadolinium borate (MGB) glasses with molar composition 25MoO3-20Gd2O3–(55 − x)B2O3−xSm2O3 (x = 0.05, 0.1, 0.5, 1.0, 2.0 mol.%) have been analyzed. The experimental oscillator strengths of absorption bands have been used to determine the Judd–Ofelt (J–O) parameters. Fluorescence spectra were recorded by exciting the samples at 402 nm. Using the J–O parameters and luminescence data, the radiative transition probabilities (AR), branching ratios (BR), and stimulated emission cross-sections oe) are obtained. The decay curves of the 4G5/2 - 6H7/2 transition exhibit a non-exponential curve fit for all concen-trations. The concentration quenching has been attributed to the energy transfer through the cross-relaxation between Sm3+ ions. 4G5/2 level and its relative quantum efficiencies are measured. Intense reddish-orange emission corresponding to the 4G5/2−6H7/2 transition has been observed in these glasses at the 487-nm excitation, From the values of the radiative parameters, it is concluded that the 1.0-mol% Sm3+-doped MGB glass may be used as a laser active medium with the emission wavelength at 599 nm. The analysis of the non-exponential behavior of decay curves through the Inokuti–Hirayama model indicates that the energy transfer between Sm3+ ions is of dipole–dipole type. The quantum efficiency for the 4G5/2 level of MGBSm10 glass is found to be 67%. The co-related color temperature obtained from CIE (Commission International de L’Eclairage) for these glass samples is ∼1620 K for the indicated orange emission at the 402-nm excitation.

Structure and microstructure of near infrared-absorbing Au–Au2S nanoparticles

2007 ◽  
Vol 22 (9) ◽  
pp. 2531-2538 ◽  
Author(s):  
Mei Chee Tan ◽  
Jackie Y. Ying ◽  
Gan Moog Chow
Keyword(s):  
Optical Properties ◽  
Surface Segregation ◽  
Near Infrared ◽  
Small Degree ◽  
Core Shell ◽  
Shell Microstructure ◽  
Absorption Bands ◽  
Interfacial Effects ◽  
Nir Absorption ◽  
Structure And Microstructure

Near infrared (NIR) absorbing nanoparticles synthesized by the reduction of HAuCl4 with Na2S exhibited absorption bands at ∼530 nm, and in the NIR region of 650–1100 nm. The NIR optical properties were not found to be related to the earlier proposed Au2S–Au core-shell microstructure in previous studies. From a detailed study of the structure and microstructure of as-synthesized particles in this work, S-containing, Au-rich, multiply-twinned nanoparticles were found to exhibit NIR absorption. They consisted of amorphous AuxS (where x = 2), mostly well mixed within crystalline Au, with a small degree of surface segregation of S. Therefore, NIR absorption was likely due to interfacial effects on particle polarization from the introduction of AuxS into Au particles, and not the dielectric confinement of plasmons associated with a core-shell microstructure.

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