scholarly journals Silicon nanocluster sensitization of erbium ions under low-energy optical excitation

2012 ◽  
Vol 111 (9) ◽  
pp. 094314 ◽  
Author(s):  
Nikola Prtljaga ◽  
Daniel Navarro-Urrios ◽  
Alessandro Pitanti ◽  
Federico Ferrarese-Lupi ◽  
Blas Garrido ◽  
...  
Keyword(s):  
Optical Excitation ◽  
Low Energy ◽  
Erbium Ions

LOW ENERGY OPTICAL EXCITATION IN CeB6

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-737-C8-738
Author(s):  
Y. S. Kwon ◽  
S. Kimura ◽  
T. Nanba ◽  
S. Kunii ◽  
M. Ikezawa ◽  
...  
Keyword(s):  
Optical Excitation ◽  
Low Energy

Effective optical excitation and resonant luminescence of erbium ions in the spectral region of eigenmodes of a planar microcavity

2007 ◽  
Vol 33 (11) ◽  
pp. 976-979 ◽  
Author(s):  
A. V. Medvedev ◽  
A. A. Dukin ◽  
A. B. Pevtsov ◽  
C. Sibilia ◽  
N. A. Feoktistov ◽  
...  
Keyword(s):  
Spectral Region ◽  
Optical Excitation ◽  
Erbium Ions ◽  
Planar Microcavity

scholarly journals The Processes of Energy Transformation in Activated Laser Materials with Ions Er3 (Review)

2015 ◽  
Vol 16 (2) ◽  
pp. 245-252 ◽  
Author(s):  
A.H. Kevshyn ◽  
V. V. Halyan ◽  
T. A. Semenyuk
Keyword(s):  
Chalcogenide Glasses ◽  
Energy Levels ◽  
Excitation Energy Transfer ◽  
Optical Excitation ◽  
Cross Relaxation ◽  
Energy Transformation ◽  
Laser Materials ◽  
Erbium Ions ◽  
Erbium Doped ◽  
Transformation Processes

In paper the features of energy transformation processes in activated with erbium ions laser materials based on optical transitions in 4f shell of Er3+ ionwere discussed. Methods of excitation of the luminescence in chalcogenide glasses doped with Er3+ ions were described and found how its intensity depends on concentration of the ions. Up-conversion and cross-relaxation play an important role in the transformation of excitations in erbium-doped materials. In cross-relaxation the energy of one center can be nonradiatively transferred to another center or divided between the two centers, while in the up-conversion, however, energy of several centers summed up in one center, bringing it acts as an additional channel of luminescence quenching, or as a way of pumping of the higher energy levels. To improve the efficiency of optical excitation of many laser materials doped with erbium ions the sensitization with ytterbium ions that have intense absorption band in the range of ~0.9-1 µm with "effective" width of about 1000 cm-1 as well a channel of the efficient nonradiative excitation energy transfer to Er3+ ions is widely used. 

Optical Excitation and Polarization in Low-Energy Collisions ofHe++H2

1972 ◽  
Vol 6 (3) ◽  
pp. 1036-1048 ◽  
Author(s):  
R. C. Isler ◽  
R. D. Nathan
Keyword(s):  
Optical Excitation ◽  
Low Energy

Optical excitation with very low energy ions

1965 ◽  
Vol 15 (21) ◽  
pp. 815-819 ◽  
Author(s):  
M. Lipeles ◽  
R. Novick ◽  
N. Tolk
Keyword(s):  
Optical Excitation ◽  
Low Energy ◽  
Low Energy Ions

Low-energy optical excitation in rare-earth hexaborides

1994 ◽  
Vol 50 (3) ◽  
pp. 1406-1414 ◽  
Author(s):  
Shin-ichi Kimura ◽  
Takao Nanba ◽  
Satoru Kunii ◽  
Tadao Kasuya
Keyword(s):  
Rare Earth ◽  
Optical Excitation ◽  
Low Energy

Population Dynamics of Excitons in Silicon Nanocrystals Structures under Strong Optical Excitation

2007 ◽  
Vol 31 ◽  
pp. 196-198
Author(s):  
Olga A. Shalygina ◽  
Denis M. Zhigunov ◽  
Dmitrii A. Palenov ◽  
Victor Timoshenko ◽  
Pavel K. Kashkarov ◽  
...  
Keyword(s):  
Silicon Nanocrystals ◽  
Optical Excitation ◽  
Coupled System ◽  
Rate Equations ◽  
Exciton Luminescence ◽  
Sio2 Matrix ◽  
Erbium Ions ◽  
Si Nanocrystals ◽  
Er Doped ◽  
Experimental And Theoretical Studies

We report on the experimental and theoretical studies of population/depopulation dynamics of excitons in the structures with Si nanocrystals in SiO2 matrix (nc-Si/SiO2) under strong optical excitation. The experimental results are explained using a phenomenological model based on rate equations for coupled system of energy donors (excitons) and energy acceptors (erbium ions). Exciton luminescence is found to exhibit superlinear dependence for Er-doped samples. At the same time the Er-related luminescence at 1.5 μm shows a saturation of the intensity and shortening of the lifetime, which are attributed to the population inversion of the Er ions states. The obtained results demonstrate that nc-Si/SiO2:Er systems can be used for applications in Si-based optical amplifiers and lasers, compatible with planar Si-technology.

Dissociated Σ=27 boundaries in silicon

1988 ◽  
Vol 46 ◽  
pp. 624-625
Author(s):  
A. Garg ◽  
W.A.T. Clark ◽  
J.P. Hirth
Keyword(s):  
Electron Diffraction ◽  
Local Minimum ◽  
Boundary Energy ◽  
Coincidence Site Lattice ◽  
Boundary Plane ◽  
Low Energy ◽  
Theoretical Understanding ◽  
Site Lattice ◽  
Kikuchi Pattern ◽  
Analysis Techniques

In the last twenty years, a significant amount of work has been done in the theoretical understanding of grain boundaries. The various proposed grain boundary models suggest the existence of coincidence site lattice (CSL) boundaries at specific misorientations where a periodic structure representing a local minimum of energy exists between the two crystals. In general, the boundary energy depends not only upon the density of CSL sites but also upon the boundary plane, so that different facets of the same boundary have different energy. Here we describe TEM observations of the dissociation of a Σ=27 boundary in silicon in order to reduce its surface energy and attain a low energy configuration.The boundary was identified as near CSL Σ=27 {255} having a misorientation of (38.7±0.2)°/[011] by standard Kikuchi pattern, electron diffraction and trace analysis techniques. Although the boundary appeared planar, in the TEM it was found to be dissociated in some regions into a Σ=3 {111} and a Σ=9 {122} boundary, as shown in Fig. 1.

Transfer optics for high spatial resolution electron spectroscopy

1988 ◽  
Vol 46 ◽  
pp. 666-667
Author(s):  
G. G. Hembree ◽  
Luo Chuan Hong ◽  
P.A. Bennett ◽  
J.A. Venables
Keyword(s):  
Magnetic Field ◽  
Scanning Transmission Electron Microscope ◽  
Low Energy ◽  
Objective Lens ◽  
State University ◽  
Arizona State University ◽  
Initial Field ◽  
Resolution Electron ◽  
Scanning Transmission ◽  
Low Energy Electrons

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

Performance Evaluation of a Novel Type of Low-Energy Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 354-355
Author(s):  
Bertholdand Senftinger ◽  
Helmut Liebl
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Strength ◽  
Numerical Aperture ◽  
Low Energy ◽  
Energy Electron ◽  
High Resolution Imaging ◽  
Lens System ◽  
Resolution Imaging ◽  
Low Energy Electron

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.

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