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.

Spectral Investigations of Dy3+-Doped Gd2O3-CaO-P2O5 Glasses

2016 ◽  
Vol 675-676 ◽  
pp. 384-388 ◽  
Author(s):  
Piyachat Meejitpaisan ◽  
Chittra Kedkaew ◽  
C.K. Jayasankar ◽  
Jakrapong Kaewkhao
Keyword(s):  
Absorption Spectra ◽  
Emission Spectra ◽  
Ground Level ◽  
Phosphate Glasses ◽  
Absorption Bands ◽  
Quenching Effect ◽  
Ion Concentrations ◽  
Increase With Increase ◽  
Doped Glasses ◽  
Doped Glass

Dy3+-doped phosphate glasses of the compositions 20Gd2O3 : 10CaO : (70-x)P2O5 : xDy2O3, where x = 0.05, 0.10, 0.50, 1.00 and 1.50 mol% have been prepared by melt quenching technique and characterized by optical absorption, emission spectra and decay curve analysis. All the transitions in the absorption spectra are originated from the 6H15/2 ground level to the various excited states and these are intra configuration (f-f) transitions. The observed twelve absorption bands centered at 349, 362, 387, 425, 451, 473, 750, 800, 895, 1089, 1266 and 1676 nm are assigned to 6P7/2, 4P3/2, 4F7/2, 4G11/2, 4I15/2, 4F9/2, 6F3/2, 6F5/2, 6F7/2, 6F9/2, 6H9/2 and 6H11/2 transitions, respectively. The absorption spectra of glasses increase with increase in Dy3+ ion concentrations. The emission spectra of Dy3+-doped glasses are observed to be centered at 483, 573, 662 and 752 nm originated from the 4F9/2→6H15/2, 4F9/2→6H13/2, 4F9/2→6H11/2 and 4F9/2→6H9/2 transitions, respectively under excitation at 349 nm. The highest emission intensity of Dy3+-doped glass is 0.50 mol% due to concentration quenching effect. The experimental lifetimes are found to decrease when Dy3+ ion concentrations increased due to energy transfer process between Dy3+ ions.

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.

Optical Analysis of RE3+: Boro-Fluoro-Phosphate Glasses

2010 ◽  
Vol 161 ◽  
pp. 13-41
Author(s):  
B. Sudhakar Reddy ◽  
S. Buddhudu
Keyword(s):  
Absorption Spectra ◽  
Emission Spectra ◽  
Green Emission ◽  
Phosphate Glasses ◽  
Radiative Properties ◽  
Composition Series ◽  
Absorption Bands ◽  
Intensity Parameters ◽  
Doped Glasses ◽  
Nir Emission

We report here on the preparation and optical characterization of certain rare earth (Nd3+,Tb3+,Pr3+ &Tm3+ each in 0.2 mol %) ions doped in two new series glasses in the following composition: Series A: 69.8 B2O3 – 10 P2O5 – 10(ZnO/CdO/TeO2) – 10 AlF3 Series B: 69.8 B2O3 – 10 P2O5 – 10(ZnO/CdO/TeO2) – 10 LiF By applying the Judd-Ofelt intensity parameters of Nd3+: BFP glasses, radiative properties of the emission transitions ( 4F3/2 ®4IJ=9/2, 11/2 &13/2 ) at 906, 1079 and 1349nm have been evaluated. By applying the Judd-Ofelt intensity parameters, radiative properties for Er3+ ions doped glasses, the NIR emission (4I13/2 4I15/2 ) at 1547nm , and also visible green emission (4S3/2 4I15/2 ) at 547nm have been evaluated. Measured absorption spectra of Pr3+: BFP glasses have shown eight absorption bands at 443, 469, 481, 589 , 1008, 1419, 1523 and 1930 nm which correspond to the transitions 3H4 ®3P2, 3P1, 3P0, 1D2, 1G4,3F4, 3F3 and 3F2 respectively. Absorption spectra of Tm3+: glasses have revealed five absorption bands at 466, 685, 790, 1206 and 1644 nm which corresponding to the transitions 3H6®1G4, 3F3, 3H4, 3H5 and 3F4 respectively. Pr3+: glasses, with an excitation at 442nm (3H4 ®3P2), a orange-red emission at 600 nm (1D2® 3H4) has been observed. In the case of Tm3+: glasses, upon excitation with 355nm (3H6®1D2), blue emissions at 452 nm (1D2®3F4) and at 476 nm (1G4®3H6) are observed. From the measured NIR emission spectra of Pr3+: BFP glasses, an NIR emission at 1354nm (1G4®3H5) and form Tm3+: glasses, an NIR emission (3F4®3H6) at 1809 nm are observed with an Ar+ laser (514.5 nm) as the excitation source.

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.

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.

Composition, particle size, and near-infrared irradiation effects on optical properties of Au–Au2S nanoparticles

2008 ◽  
Vol 23 (1) ◽  
pp. 281-293 ◽  
Author(s):  
Mei Chee Tan ◽  
Jackie Y. Ying ◽  
Gan Moog Chow
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Thermal Effects ◽  
Near Infrared ◽  
Sodium Sulfide ◽  
Irradiation Effects ◽  
Absorption Bands ◽  
Molar Ratios ◽  
Nir Absorption ◽  
Structure And Microstructure

Near-infrared (NIR)-absorbing nanoparticles synthesized by the reduction of tetrachloroauric acid (HAuCl4) using sodium sulfide (Na2S) exhibited absorption bands at ∼530 nm and at the NIR region of 650−1100 nm. A detailed study on the structure and microstructure of as-synthesized nanoparticles was reported previously. The as-synthesized nanoparticles were found to consist of amorphous AuxS (x = ∼2), mostly well mixed within crystalline Au. In this work, the optical properties were tailored by varying the precursor molar ratios of HAuCl4 and Na2S. In addition, a detailed study of composition and particle-size effects on the optical properties was discussed. The change of polarizability by the introduction of S in the form of AuxS (x = ∼2) had a significant effect on NIR absorption. Also, it was found in this work that exposure of these particles to NIR irradiation using a Nd:YAG laser resulted in loss of the NIR absorption band. Thermal effects generated during NIR irradiation had led to microstructural changes that modified the optical properties of particles.

Laser Power Density Dependence in Absorption Measurements

1980 ◽  
Vol 34 (3) ◽  
pp. 311-313
Author(s):  
Peter M. Castle
Keyword(s):  
Power Density ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Continuous Wave ◽  
Strong Dependence ◽  
Wave Mode ◽  
Input Power ◽  
Absorption Cross ◽  
Continuous Wave Mode ◽  
Absorption Measurements

The absorption cross section of CF2Cl2 has been measured as a function of presure and CO2 laser input power at 10.764 μm. The laser was operated in the continuous wave mode providing a continuous energy deposition in the sample. It is shown that the absorption cross section measured has a strong dependence on input power density in the range from 5 to 15 W/cm2 and pressure in the 3 to 50 Torr regime. It is demonstrated that most of these effects can be attributed to the temperature rise in the beam interaction volume.

scholarly journals Applications of the Advanced Radiative Transfer Modeling System (ARMS) to Characterize the Performance of Fengyun–4A/AGRI

2021 ◽  
Vol 13 (16) ◽  
pp. 3120
Author(s):  
Fei Tang ◽  
Xiaoyong Zhuge ◽  
Mingjian Zeng ◽  
Xin Li ◽  
Peiming Dong ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Strong Dependence ◽  
Final Analysis ◽  
Analysis Data ◽  
Water Vapor Absorption ◽  
Absorption Bands ◽  
Geostationary Meteorological Satellite ◽  
Environmental Prediction ◽  
Radiative Transfer Modeling ◽  
Ir Bands

This study applies the Advanced Radiative Transfer Modeling System (ARMS), which was developed to accelerate the uses of Fengyun satellite data in weather, climate, and environmental applications in China, to characterize the biases of seven infrared (IR) bands of the Advanced Geosynchronous Radiation Imager (AGRI) onboard the Chinese geostationary meteorological satellite, Fengyun–4A. The AGRI data are quality controlled to eliminate the observations affected by clouds and contaminated by stray lights during the mid–night from 1600 to 1800 UTC during spring and autumn. The mean biases, computed from AGRI IR observations and ARMS simulations from the National Center for Environmental Prediction (NCEP) Final analysis data (FNL) as input, are within −0.7–1.1 K (0.12–0.75 K) for all seven IR bands over the oceans (land) under clear–sky conditions. The biases show seasonal variation in spatial distributions at bands 11–13, as well as a strong dependence on scene temperatures at bands 8–14 and on satellite zenith angles at absorption bands 9, 10, and 14. The discrepancies between biases estimated using FNL and the European Center for Medium–Range Weather Forecasts Reanalysis–5 (ERA5) are also discussed. The biases from water vapor absorption bands 9 and 10, estimated using ERA5 over ocean, are smaller than those from FNL. Such discrepancies arise from the fact that the FNL data are colder (wetter) than the ERA5 in the middle troposphere (upper–troposphere).

scholarly journals Evaluating biases in filter-based aerosol absorption measurements using photoacoustic spectroscopy

2019 ◽  
Vol 12 (6) ◽  
pp. 3417-3434 ◽  
Author(s):  
Nicholas W. Davies ◽  
Cathryn Fox ◽  
Kate Szpek ◽  
Michael I. Cotterell ◽  
Jonathan W. Taylor ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Photoacoustic Spectroscopy ◽  
Strong Dependence ◽  
Single Scattering ◽  
Aerosol Absorption ◽  
Aerosol Mass ◽  
Correction Scheme ◽  
Measurement Biases ◽  
Absorption Photometer ◽  
Absorption Measurements

Abstract. Biases in absorption coefficients measured using a filter-based absorption photometer (Tricolor Absorption Photometer, or TAP) at wavelengths of 467, 528 and 652 nm are evaluated by comparing to measurements made using photoacoustic spectroscopy (PAS). We report comparisons for ambient sampling covering a range of aerosol types including urban, fresh biomass burning and aged biomass burning. Data are also used to evaluate the performance of three different TAP correction schemes. We found that photoacoustic and filter-based measurements were well correlated, but filter-based measurements generally overestimated absorption by up to 45 %. Biases varied with wavelength and depended on the correction scheme applied. Optimal agreement to PAS data was achieved by processing the filter-based measurements using the recently developed correction scheme of Müller et al. (2014), which consistently reduced biases to 0 %–18 % at all wavelengths. The biases were found to be a function of the ratio of organic aerosol mass to light-absorbing carbon mass, although applying the Müller et al. (2014) correction scheme to filter-based absorption measurements reduced the biases and the strength of this correlation significantly. Filter-based absorption measurement biases led to aerosol single-scattering albedos that were biased low by values in the range 0.00–0.07 and absorption Ångström exponents (AAEs) that were in error by ± (0.03–0.54). The discrepancy between the filter-based and PAS absorption measurements is lower than reported in some earlier studies and points to a strong dependence of filter-based measurement accuracy on aerosol source type.

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