Erbium Doped Tellurite Glasses

1991 ◽  
Vol 244 ◽  
Author(s):  
Jau-Sheng Wang ◽  
Elias Snitzer ◽  
George H. Sigel
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Optical Transition ◽  
Emission Cross Section ◽  
Excited State Absorption ◽  
Tellurite Glasses ◽  
Ground State Absorption ◽  
Erbium Doped

ABSTRACTThe results to be presented focus on the optimization of tellurite glass compositions which are suitable both for doping with erbium oxide as well as subsequent for fiber drawing. The laser related properties, such as fluorescence spectrum, lifetime, and optical transition cross sections will be presented. Judd-Ofelt parameters for erbium in the glasses have been exploited to predict fluorescence lifetime, excited state absorption(ESA), ground state absorption(GSA) and ground state fluorescence(GSF). For comparison, the absorption cross section, emission cross section, excited state absorption(ESA)/ground state absorption(GSA)(0.8μm pumping) and fluorescence terminating in the ground state(GSF)/excited state absorption(ESA) ratios are calculated for both Al2O3-SiO2 and tellurite glasses.

Excited State Absorption and Cross Sections for Er-Doped Glasses

1989 ◽  
Vol 172 ◽  
Author(s):  
S. Zemon ◽  
G. Lambert ◽  
W. J. Miniscalco ◽  
L. J. Andrews ◽  
B. T. Hall
Keyword(s):  
Excited State ◽  
Excited States ◽  
Cross Sections ◽  
Ground State ◽  
Excited State Absorption ◽  
Fiber Amplifiers ◽  
Oscillator Strengths ◽  
Ground State Absorption ◽  
Doped Glasses ◽  
Er Doped

AbstractPump-excited-state-absorption (ESA) measurements on Er3+-doped phosphates, fluorophosphates, and silicate bulk glasses indicate that ESA cross sections are approximately equal to ground state absorption (GSA) cross sections in the 800-nm band. The oscillator strengths of the ESA and GSA bands are also approximately equal, in qualitative agreement with Judd-Ofelt calculations. Fluorozirconate samples were found to have substantial populations in the upper excited states for the measurement conditions used and ESA transitions originating from four excited states were identified. Fluorozirconate fiber amplifiers and lasers at 1.55 μm, therefore, would have decreased efficiency for 800-nm pumping.

Infrared saturable absorbers. Part I: Five-level rate-equation analysis

1977 ◽  
Vol 55 (3) ◽  
pp. 243-251
Author(s):  
Tuan-Kay Lim ◽  
Jerald R. Izatt ◽  
George F. Caudle
Keyword(s):  
Excited State ◽  
Cross Sections ◽  
Ground State ◽  
Excited State Absorption ◽  
Incident Radiation ◽  
Quadratic Equation ◽  
Absorption Coefficients ◽  
Ground State Absorption ◽  
Rotational States ◽  
Terminal Level

The saturation behavior of molecular absorbers characterized by absorption coefficients expressible as the ratio of two polynomials in the intensity is analyzed. Two cases are considered in detail. In the first, the absorption coefficient is the ratio of a linear equation in I to a quadratic equation in I. In the second, the highest order of the intensity occurring in both numerator and denominator is increased by two. The absorption coefficients are derived from two specific five-level models which are pertinent to the interpretation of the absorption of CO2 laser radiation at 937 cm−1 by SF6, but the analysis of the saturation curves is independent of the models from which they are derived. The saturation curves display as many as three extrema and provide considerable flexibility for fitting complicated experimental data. Both five-level models include excited-state absorption with the terminal level of the ground-state absorption distinct from the initial level of the excited-state absorption. Each of the five levels can be considered as a composite of many rotational states which interact in a like manner with the incident radiation. In one of the models the ratio of the excited-state and ground-state absorption cross sections is taken to be intensity dependent.

Photoneutron cross sections in 7Li

1977 ◽  
Vol 55 (5) ◽  
pp. 428-433 ◽  
Author(s):  
H. Ferdinande ◽  
N. K. Sherman ◽  
K. H. Lokan ◽  
C. K. Ross
Keyword(s):  
Fine Structure ◽  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Reasonable Agreement ◽  
Branching Ratio ◽  
Energy Spectra ◽  
Average Value ◽  
First Excited State

Photoneutron energy spectra from 7Li have been measured by time-of-flight methods, for bremsstrahlung end-point energies increasing in 2 MeV steps from 13 to 25 MeV. The ground-state and approximate first-excited-state differential cross sections at 90° have been obtained from 8.5 to 23 MeV. No pronounced fine structure has been observed. The measured branching ratio to the first excited state falls from an average value of 0.70 between 10.3 and 14.5 MeV to an average of 0.29 between 14.5 and 18 MeV, and rises again to an average of 0.38 between 18 and 23 MeV. This behaviour can be explained by a crude theoretical model in which 1p → 2s and 1p → 1d single particle transitions dominate below 18 MeV. The calculation predicts a branching ratio of 0.50 near threshold, falling to 0.23 at higher energies, in reasonable agreement with the experiment. The integrated value of the ground-state cross section up to 23 MeV is about (38.7 ± 3.9) MeV mb, while that for the first excited state is about (17.2 ± 3.4) MeV mb. Together they account for 39% of the exchange-augmented dipole sum of 7Li.

Photoneutron Reactions in 18O

1975 ◽  
Vol 53 (8) ◽  
pp. 786-794 ◽  
Author(s):  
J. D. Allan ◽  
J. W. Jury ◽  
R. G. Johnson ◽  
K. G. McNeill ◽  
J. G. Woodworth ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Ground State ◽  
Energy Spectra ◽  
Continuum State ◽  
Average Value ◽  
First Excited State ◽  
Time Of Flight Spectroscopy

Photoneutron energy spectra from 18O have been measured by time-of-flight spectroscopy at bremsstrahlung endpoint energies from 11 to 18 MeV in 1 MeV steps to obtain the (γ, n0) and (γ, n1) differential cross sections. The ground state photoneutron cross section contains at least 8 major resonances in the region from 10 to 17 MeV and has an average value of 100 μb/sr. The cross section to the first excited state of 17O contains only two major resonances, at 11.4 and 14.4 MeV, and the average cross section in the region from 11 to 16 MeV is about 40 μb/sr. Of particular interest is a resonance at 14.4 MeV which appears to reflect a simple excitation of one of the valence neutrons to the 2p3/2 state. Analysis of the (γ, n0) and (γ, n1) cross sections for this continuum state leads to estimates of the configuration amplitudes of the 2s1/2 and 1d5/2 components of this state to be 0.62 ± 0.06 and 0.78 ± 0.08 respectively and the ratio of the (2s1/2)2 to (1d5/2)2 amplitudes in the ground state of 18O to be 0.39 ± 0.02.

scholarly journals Investigation of upconversion phenomenon in Y1-xLn3+x(BTC)(DMF)2(H2O) and Y0.8-xYb0.2Ln3+x(BTC)(DMF)2(H2O) metal organic frameworks

Chemija ◽  
2021 ◽  
Vol 32 (2) ◽  
Author(s):  
Andrius Laurikėnas ◽  
Aivaras Kareiva
Keyword(s):  
Excited State ◽  
Carboxylic Acid ◽  
Ground State ◽  
Ion Pairs ◽  
Metal Organic Frameworks ◽  
Excited State Absorption ◽  
Tricarboxylic Acid ◽  
Lanthanide Ions ◽  
Ground State Absorption ◽  
Metal Organic

In this study, Y1-xLn3+x(BTC)(DMF)2(H2O) and Y0.8-xYb0.2Ln3+x(BTC)(DMF)2(H2O) metal organic frameworks (MOFs), which structure included lanthanide ions, Ln3+ (Er3+, Ho3+, Tm3+, Yb3+, Nd3+), suitable for monitoring the upconversion phenomenon, have been synthesised. For this purpose the precursor of the organic moiety, benzene-1,3,5-tricarboxylic acid (BTC), as one of the simplest and very frequently cited carboxylic acid analogues in MOF syntheses, has been selected. By characterising upconversion properties of new MOFs it was determined that only Er3+ can be used as an activator for one centre luminescence upconversion by a ground state absorption/ excited-state absorption (GSA/ESA) mechanism, while with Yb3+, Ho3+, Tm3+ and Nd3+ ions the upconversion was not observed. It was also established that BTC cannot initiate triplet–triplet annihilation upconversion (TTA-UC) as this mechanism sensitizer. Yb3+–Er3+ and Yb3+–Ho3+ ion pairs as a sensitizeractivator were suitable for two-centre luminescence upconversion by a GSA/ excited-state upconversion (GSA/ESU) mechanism. A pair of Yb3+–Tm3+, contrary as shown in the literature review, does not exhibit upconversion properties in the synthesised MOFs.

Cross sections of excited-state absorption at 800 nm in erbium-doped ZBLAN fiber

1998 ◽  
Vol 67 (1) ◽  
pp. 23-28 ◽  
Author(s):  
M. Pollnau ◽  
C. Ghisler ◽  
W. Lüthy ◽  
H.P. Weber
Keyword(s):  
Excited State ◽  
Cross Sections ◽  
Excited State Absorption ◽  
Erbium Doped

The S1 → Sn and T1→ TnAbsorption Spectra of Some Anthracene Derivatives

1985 ◽  
Vol 40 (8) ◽  
pp. 849-858 ◽  
Author(s):  
Jan Szczepański ◽  
Józef Heidt
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Aromatic Compounds ◽  
Room Temperature ◽  
Excited State Absorption ◽  
Laser Flash ◽  
Absorption Cross ◽  
Anthracene Derivatives

A method for the determination of excited state absorption cross section spectra with a laser flash spectrometer is demonstrated. In the region 405-660 nm the cross sections of seven aromatic compounds in not degased dioxan at room temperature have been determined. The data obtained for anthracene are compared with those of other authors.

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