Yurii Uspenskii
Russian Academy of Sciences
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Featured researches published by Yurii Uspenskii.
Optics Letters | 1998
Yurii Uspenskii; Levashov Ve; Aleksandr V. Vinogradov; Fedorenko Ai; Valeriy V. Kondratenko; Pershin Yp; Zubarev En; Fedotov Vy
Sc-Si multilayers are suggested as high-reflectivity coatings for a VUV interval of 35-50 nm. Fabricated mirrors show normal-incidence reflectivity of 30-54%, which is high enough for effective manipulation of the beams of compact-discharge, laser-driven x-ray lasers. The values obtained are not, however, limits for Sc-Si coatings. Theoretical estimations as well as electron microscopy studies of Sc-Si interfaces indicate a large potential for a further increase in their reflectivity.
Optics Letters | 2011
Svetlana S. Aleshkina; Mikhail E. Likhachev; Andrey D. Pryamikov; Dmitry A. Gaponov; Alexandr N. Denisov; Mikhail M. Bubnov; M.Y. Salganskii; Alexandr Yu. Laptev; Yurii Uspenskii; Nikolay Popov; Sébastien Février
A design of a polarizing all-glass Bragg fiber with a microstructure core has been proposed for the first time. This design provides suppression of high-order modes and of one of the polarization states of the fundamental mode. The polarizing fiber was fabricated by a new, simple method based on a combination of the modified chemical vapor deposition (MCVD) process and the rod-in-tube technique. The mode field area has been found to be about 870 μm² near λ=1064 nm. The polarization extinction ratio better than 13 dB has been observed over a 33% wavelength range (from 1 to 1.4 μm) after propagation in a 1.7 m fiber piece bent to a radius of 70 cm.
Nanoscale | 2016
Sergey Lepeshkin; V. A. Baturin; Evgeny V. Tikhonov; N L Matsko; Yurii Uspenskii; Anastasia Naumova; Oleg D. Feya; Martin A. A. Schoonen; Artem R. Oganov
Oxidation of silicon nanoclusters depending on the temperature and oxygen pressure is explored from first principles using the evolutionary algorithm, and structural and thermodynamic analysis. From our calculations of 90 SinOm clusters we found that under normal conditions oxidation does not stop at the stoichiometric SiO2 composition, as it does in bulk silicon, but goes further placing extra oxygen atoms on the cluster surface. These extra atoms are responsible for light emission, relevant to reactive oxygen species and many of them are magnetic. We argue that the super-oxidation effect is size-independent and discuss its relevance to nanotechnology and miscellaneous applications, including biomedical ones.
Solid State Phenomena | 2015
L. A. Aslanov; I. K. Kudryavtsev; V.N. Zakharov; Erkin Kulatov; Yurii Uspenskii
Silicon (Si) is currently the basis of most of nanodevice technology, therefore ultrathin materials based on Si have the great advantage of easy integration into existing circuitry. First flat silicon nanoparticles have been obtained with perfluorophenyl (PFPh) ligand coating. The size of these particles varied from 15 to 50 nm. Their thickness evaluated with the atomic force microscopy was about 3.3 nm. Based on ab initio DFT calculations we investigate the geometries and electronic structures of free-standing PFPh-stabilized 2D silicon in order to see if such systems have promising electronic and optical properties. We also examined the effect of doping PFPh-stabilized 2D silicon by the Mn atoms.
Solid State Phenomena | 2015
V. A. Baturin; Sergey Lepeshkin; N L Matsko; Yurii Uspenskii
The total energy, geometry and electronic spectra of nanoclusters \shm{} (
Journal of Magnetism and Magnetic Materials | 2014
Samuel Tardif; Andrey Titov; Emmanuel Arras; Ivetta Slipukhina; E.K. Hlil; S. Cherifi; Yves Joly; Matthieu Jamet; A. Barski; J. Cibert; Erkin Kulatov; Yurii Uspenskii; Pascal Pochet
m=0\ldots11
Solid State Phenomena | 2012
M V Magnitskaya; Erkin Kulatov; Andrey Titov; Yurii Uspenskii; Evgenii G. Maksimov; S. V. Popova; Vadim V. Brazhkin
) are calculated using the evolutionary algorithm and density functional theory (DFT). It is shown, that the features of electron spectrum, namely HOMO-LUMO gap and valence band width, correlate with cluster geometry and stability. The HOMO-LUMO gap becomes wider as the number of hydrogen atoms increases whereas the width of valence band gets lower. The widening of the band gap indicates the increasing of cluster stability which is consistent with existing data on reaction energy.
Solid State Phenomena | 2012
Erkin Kulatov; Andrey Titov; Yurii Uspenskii
X-ray absorption (XAS) and x-ray magnetic circular dichroism (XMCD) spectra at the L
International Journal of Quantum Chemistry | 2013
Erkin Kulatov; Maria Magnitskaya; Yurii Uspenskii; Svetlana Popova; Vadim V. Brazhkin; Evgenii G. Maksimov
_{2,3}
Physical Review B | 2010
Andrey Titov; Fabienne Michelini; L. Raymond; Erkin Kulatov; Yurii Uspenskii
edges of Mn in (Ge,Mn) compounds have been measured and are compared to the results of first principles calculation. Early \textit{ab initio} studies show that the Density Functional Theory (DFT) can very well describe the valence band electronic properties but fails to reproduce a characteristic change of sign in the L