Effect of excitation conditions on photostability of 2-(4pyridyl)-5 phenyl)oxazole laser media

1995 ◽  
Author(s):  
Rimma T. Kuznetsova ◽  
Tat'yana N. Kopylova ◽  
K. M. Degtjarenko ◽  
Evgenii N. Tel'minov ◽  
Lyibov G. Samsonova ◽  
...  
Keyword(s):  
Laser Media ◽  
Excitation Conditions

A New Numerical Model for Electron-Probe Analysis at High Depth Resolution

1996 ◽  
Vol 54 ◽  
pp. 490-491
Author(s):  
P.-F. Staub ◽  
C. Bonnelle ◽  
F. Vergand ◽  
P. Jonnard
Keyword(s):  
Electron Probe ◽  
Surface Segregation ◽  
Depth Distribution ◽  
Computing Time ◽  
Depth Resolution ◽  
Physical Parameters ◽  
Electron Probe Analysis ◽  
Interface Phases ◽  
Excitation Conditions ◽  
High Depth

Characterizing dimensionally and chemically nanometric structures such as surface segregation or interface phases can be performed efficiently using electron probe (EP) techniques at very low excitation conditions, i.e. using small incident energies (0.5<E0<5 keV) and low incident overvoltages (1<U0<1.7). In such extreme conditions, classical analytical EP models are generally pushed to their validity limits in terms of accuracy and physical consistency, and Monte-Carlo simulations are not convenient solutions as routine tools, because of their cost in computing time. In this context, we have developed an intermediate procedure, called IntriX, in which the ionization depth distributions Φ(ρz) are numerically reconstructed by integration of basic macroscopic physical parameters describing the electron beam/matter interaction, all of them being available under pre-established analytical forms. IntriX’s procedure consists in dividing the ionization depth distribution into three separate contributions:

scholarly journals Molecules in the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 415-420 ◽  
Author(s):  
R. S. Booth ◽  
Th. De Graauw
Keyword(s):  
High Resolution ◽  
Molecular Clouds ◽  
Short Review ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Giant Molecular Clouds ◽  
Interstellar Molecules ◽  
First Time ◽  
Excitation Conditions

In this short review we describe recent new observations of millimetre transitions of molecules in selected regions of the Magellanic Clouds. The observations were made using the Swedish-ESO Submillimetre Telescope, SEST, (Booth et al. 1989), the relatively high resolution of which facilitates, for the first time, observations of individual giant molecular clouds in the Magellanic Clouds. We have mapped the distribution of the emission from the two lowest rotational transitions of 12CO and 13CO and hence have derived excitation conditions for the molecule. In addition, we have observed several well-known interstellar molecules in the same regions, thus doubling the number of known molecules in the Large Magellanic Cloud (LMC). The fact that all the observations have been made under controlled conditions with the same telescope enables a reasonable intercomparison of the molecular column densities. In particular, we are able to observe the relative abundances among the different isotopically substituted species of CO.

scholarly journals Sulfophosphate Glass Doped with Er3+ and TiO2 Nanoparticles: Thermo-Optical Characterization by Photothermal Spectroscopy

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 115
Author(s):  
Zeinab Ebrahimpour ◽  
Humberto Cabrera ◽  
Fahimeh Ahmadi ◽  
Asghar Asgari ◽  
Joseph Niemela
Keyword(s):  
Optical Properties ◽  
Tio2 Nanoparticles ◽  
Refractive Index Change ◽  
Optical Path Length ◽  
Beam Deflection ◽  
Time Resolved ◽  
Tio2 Nps ◽  
Amorphous Glass ◽  
Laser Media ◽  
Materials Used

In this work, time-resolved thermal lens and beam deflection methods were applied to determine the thermo-optical properties of Er3+ doped sulfophosphate glass in which different concentrations of Titanium dioxide (TiO2) nanoparticles (NPs) were embedded. Thermal diffusivity (D), thermal conductivity (κ), and the temperature coefficient of the optical path length (ds/dT) were determined as a function of NPs concentrations. Moreover, the growth of TiO2 NPs inside the amorphous glass matrix was evidenced by Transmission Electron Microscopy (TEM) images as well as through optical effects such as refractive index change of the glass. The outcomes indicated relatively high values for D and κ as well as a low ds/dT as required for most optical components used for laser media. The addition of TiO2 NPs with concentration of dopants up to 0.6 mol% improved the optical properties of the glass samples but did not affect its thermal properties. The results indicate that the enhanced optical and thermal performance of the proposed co-doped glass fits the quality standards for materials used in photonic devices.

Wave propagation in the presence of a spatially uniform external periodic magnetic field in two-temperature plasma

1982 ◽  
Vol 28 (1) ◽  
pp. 93-101
Author(s):  
Sanjay Kumar Ghosh
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Fluid Model ◽  
Hydrodynamic Equations ◽  
Temperature Plasma ◽  
Uniform External Magnetic Field ◽  
Two Fluid Model ◽  
Excitation Conditions ◽  
Two Fluid ◽  
Two Temperature

Starting from the two-fluid model hydrodynamic equations, a dispersion relation is obtained for wave propagation through a two-temperature plasma perpendicular to the direction of the spatially uniform external magnetic field B0cosω0t and several excitation conditions are deduced.

Reversible photoconversion in dye solutions in step-excitation conditions

1991 ◽  
Vol 55 (5) ◽  
pp. 1066-1069
Author(s):  
A. V. Aristov ◽  
D. A. Kozlovskii ◽  
A. B. Nikolaev
Keyword(s):  
Excitation Conditions ◽  
Dye Solutions

Micro-Photoluminescence Mapping of Defect Structures in SiC Wafers

2007 ◽  
Vol 556-557 ◽  
pp. 383-386 ◽  
Author(s):  
John Hennessy ◽  
Tom Ryan
Keyword(s):  
Carrier Lifetime ◽  
Deep Level ◽  
Complex Function ◽  
Band Edge ◽  
Structural Defects ◽  
Band Edge Emission ◽  
Interfacial Defects ◽  
Pl Mapping ◽  
Boron Acceptor ◽  
Excitation Conditions

Micro-photoluminescence can be used to image electrically active structural defects in SiC. Under suitable excitation conditions it is possible to observe both band-edge PL and near bandedge PL from recombination via a shallow boron acceptor. The intensity of the band-edge emission is related to the carrier lifetime – and is reduced by the presence of structural or interfacial defects. The intensity of the deep level PL is a complex function of the number of radiative centers and the number of centers limiting carrier lifetime. Micro-PL mapping can provide information on the spatial distribution of electrically active defects in SiC.

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