The Experts below are selected from a list of 15615 Experts worldwide ranked by ideXlab platform
Andrey Surzhykov - One of the best experts on this subject based on the ideXlab platform.
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angular distribution studies on the two photon ionization of hydrogen like ions relativistic description
arXiv: Atomic Physics, 2007Co-Authors: Peter Koval, Sebastian Fritzsche, Andrey SurzhykovAbstract:The angular distribution of the emitted electrons, following the two-photon ionization of the hydrogen-like ions, is studied within the framework of second order perturbation theory and the Dirac equation. Using a density matrix approach, we have investigated the effects which arise from the polarization of the Incoming Light as well as from the higher multipoles in the expansion of the electron--photon interaction. For medium- and high-Z ions, in particular, the non-dipole contributions give rise to a significant change in the angular distribution of the emitted electrons, if compared with the electric-dipole approximation. This includes a strong forward emission while, in dipole approxmation, the electron emission always occurs symmetric with respect to the plane which is perpendicular to the photon beam. Detailed computations for the dependence of the photoelectron angular distributions on the polarization of the incident Light are carried out for the ionization of H, Xe$^{53+}$, and U$^{91+}$ (hydrogen-like) ions.
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electron angular distributions in the two photon ionization of hydrogen like ions a relativistic description
Journal of Physics B, 2004Co-Authors: Peter Koval, Sebastian Fritzsche, Andrey SurzhykovAbstract:The angular distribution of the emitted electrons, following the two-photon ionization of hydrogen-like ions, is studied within the framework of second order perturbation theory and the Dirac equation. Using a density matrix approach, we have investigated the effects which arise from the polarization of the Incoming Light as well as from the higher multipoles in the expansion of the electron–photon interaction. For medium- and high-Z ions, in particular, the non-dipole contributions give rise to a significant change in the angular distribution of the emitted electrons, if compared with the electric dipole approximation. This includes a strong forward emission while, in the dipole approximation, the electron emission always occurs symmetrically with respect to the plane which is perpendicular to the photon beam. Detailed computations for the dependence of the photoelectron angular distributions on the polarization of the incident Light are carried out for the ionization of H, and Xe53+ and U91+ (hydrogen-like) ions.
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electron angular distributions in the two photon ionization of hydrogen like ions relativistic description
arXiv: Atomic Physics, 2003Co-Authors: Peter Koval, Sebastian Fritzsche, Andrey SurzhykovAbstract:The angular distribution of the emitted electrons, following the two--photon ionization of the hydrogen--like ions, is studied within the framework of second order perturbation theory \textit{and} the Dirac equation. Using a density matrix approach, we have investigated the effects which arise from the polarization of the Incoming Light as well as from the higher multipoles in the expansion of the electron--photon interaction. For medium-- and high--Z ions, in particular, the non--dipole contributions give rise to a significant change in the angular distribution of the emitted electrons, if compared with the electric--dipole approximation. This includes a strong forward emission while, in dipole approximation, the electron emission always occurs symmetric with respect to the plane which is perpendicular to the photon beam. Detailed computations for the dependence of the photoelectron angular distributions on the polarization of the incident Light are carried out for the ionization of the H, Xe$^{53+}$ and U$^{91+}$ (hydrogen--like) ions.
Vikram L Dalal - One of the best experts on this subject based on the ideXlab platform.
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enhanced nanocrystalline silicon solar cell with a photonic crystal back reflector
Solar Energy Materials and Solar Cells, 2010Co-Authors: R Biswas, Joydeep Bhattacharya, Brian W Lewis, Nayan Chakravarty, Vikram L DalalAbstract:Nanocrystalline silicon solar cells were enhanced with a photonic crystal back-reflector. Rigorous scattering matrix simulations were used to optimize a photonic crystal back-reflector consisting of a triangular lattice of nano-holes, with a pitch near 800 nm. The photonic crystal back-reflector with a pitch of 800 nm was fabricated on the crystalline silicon substrate by photolithography and reactive-ion etching, and coated with silver and zinc oxide. Nanocrystalline silicon solar cells were grown on the patterned substrates. We observed ∼7% enhancement of the absorption and photo-generated current relative to a Ag/ZnO substrate, with an enhancement ratio of 1.5 near the band edge. Significant enhancement occurred in photon absorption at near infrared wavelengths greater than 700 nm, due to diffraction resonances of the Incoming Light.
Stephen Lin - One of the best experts on this subject based on the ideXlab platform.
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A Prism-Mask System for Multispectral Video Acquisition
IEEE Transactions on Pattern Analysis and Machine Intelligence, 2011Co-Authors: Xun Cao, Hao Du, Qionghai Dai, Xin Tong, Stephen LinAbstract:This paper presents a prism-mask system for capturing multispectral videos. The system is composed of a triangular prism, a monochrome camera, and an occlusion mask. Incoming Light beams from the scene are sampled by the occlusion mask, dispersed into their constituent spectra by the triangular prism, and then captured by the monochrome camera. Our system is capable of capturing frames with high spectral resolution at video rates. It also allows for different trade-offs between spectral and spatial resolution by adjusting the focal length of the camera. We demonstrate multispectral video acquisition with various spectral resolutions and spatial resolutions, as well as different frame rates. The effectiveness of our system is further evaluated with several applications, including human skin detection, physical material recognition, video segmentation, RGB video generation, and illumination identification.
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a prism based system for multispectral video acquisition
International Conference on Computer Vision, 2009Co-Authors: Hao Du, Xun Cao, Xin Tong, Stephen LinAbstract:In this paper, we propose a prism-based system for capturing multispectral videos. The system consists of a triangular prism, a monochrome camera, and an occlusion mask. Incoming Light beams from the scene are sampled by the occlusion mask, dispersed into their constituent spectra by the triangular prism, and then captured by the monochrome camera. Our system is capable of capturing videos of high spectral resolution. It also allows for different tradeoffs between spectral and spatial resolution by adjusting the focal length of the camera. We demonstrate the effectiveness of our system with several applications, including human skin detection, physical material recognition, and RGB video generation.
Peter Koval - One of the best experts on this subject based on the ideXlab platform.
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angular distribution studies on the two photon ionization of hydrogen like ions relativistic description
arXiv: Atomic Physics, 2007Co-Authors: Peter Koval, Sebastian Fritzsche, Andrey SurzhykovAbstract:The angular distribution of the emitted electrons, following the two-photon ionization of the hydrogen-like ions, is studied within the framework of second order perturbation theory and the Dirac equation. Using a density matrix approach, we have investigated the effects which arise from the polarization of the Incoming Light as well as from the higher multipoles in the expansion of the electron--photon interaction. For medium- and high-Z ions, in particular, the non-dipole contributions give rise to a significant change in the angular distribution of the emitted electrons, if compared with the electric-dipole approximation. This includes a strong forward emission while, in dipole approxmation, the electron emission always occurs symmetric with respect to the plane which is perpendicular to the photon beam. Detailed computations for the dependence of the photoelectron angular distributions on the polarization of the incident Light are carried out for the ionization of H, Xe$^{53+}$, and U$^{91+}$ (hydrogen-like) ions.
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electron angular distributions in the two photon ionization of hydrogen like ions a relativistic description
Journal of Physics B, 2004Co-Authors: Peter Koval, Sebastian Fritzsche, Andrey SurzhykovAbstract:The angular distribution of the emitted electrons, following the two-photon ionization of hydrogen-like ions, is studied within the framework of second order perturbation theory and the Dirac equation. Using a density matrix approach, we have investigated the effects which arise from the polarization of the Incoming Light as well as from the higher multipoles in the expansion of the electron–photon interaction. For medium- and high-Z ions, in particular, the non-dipole contributions give rise to a significant change in the angular distribution of the emitted electrons, if compared with the electric dipole approximation. This includes a strong forward emission while, in the dipole approximation, the electron emission always occurs symmetrically with respect to the plane which is perpendicular to the photon beam. Detailed computations for the dependence of the photoelectron angular distributions on the polarization of the incident Light are carried out for the ionization of H, and Xe53+ and U91+ (hydrogen-like) ions.
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electron angular distributions in the two photon ionization of hydrogen like ions relativistic description
arXiv: Atomic Physics, 2003Co-Authors: Peter Koval, Sebastian Fritzsche, Andrey SurzhykovAbstract:The angular distribution of the emitted electrons, following the two--photon ionization of the hydrogen--like ions, is studied within the framework of second order perturbation theory \textit{and} the Dirac equation. Using a density matrix approach, we have investigated the effects which arise from the polarization of the Incoming Light as well as from the higher multipoles in the expansion of the electron--photon interaction. For medium-- and high--Z ions, in particular, the non--dipole contributions give rise to a significant change in the angular distribution of the emitted electrons, if compared with the electric--dipole approximation. This includes a strong forward emission while, in dipole approximation, the electron emission always occurs symmetric with respect to the plane which is perpendicular to the photon beam. Detailed computations for the dependence of the photoelectron angular distributions on the polarization of the incident Light are carried out for the ionization of the H, Xe$^{53+}$ and U$^{91+}$ (hydrogen--like) ions.
A Forget - One of the best experts on this subject based on the ideXlab platform.
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opening of the superconducting gap in the hole pockets of ba fe 1 x co x 2 as 2 as seen via angle resolved photoelectron spectroscopy
Physical Review B, 2012Co-Authors: B Mansart, E Papalazarou, Fuglsang M Jensen, V Brouet, L Petaccia, L De Medici, G Sangiovanni, F Rullieralbenque, A ForgetAbstract:We present an angle-resolved photoelectron spectroscopy study of the changes in the electronic structure of electron-doped Ba(Fe1-xCox)(2)As-2 across the superconducting phase transition. By changing the polarization of the Incoming Light, we were able to observe the opening of the gap for the inner hole pocket alpha and to compare its behavior with the outer holelike band beta. Measurements along high-symmetry directions show that the behavior of beta is consistent with an isotropic gap opening, while sLight anisotropies are detected for the inner band alpha. The implications of these results for the s +/- symmetry of the superconducting order parameter are discussed, in relation to the nature of the different iron orbitals contributing to the electronic structure of this multiband system.
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opening of the superconducting gap in the hole pockets of ba fe1 xcox 2 as 2 as seen via angle resolved photoelectron spectroscopy
Physical Review B, 2012Co-Authors: B Mansart, E Papalazarou, Fuglsang M Jensen, V Brouet, L Petaccia, L De Medici, G Sangiovanni, F Rullieralbenque, A Forget, D ColsonAbstract:We present an angle-resolved photoelectron spectroscopy study of the changes in the electronic structure of electron-doped Ba(Fe1-xCox)(2)As-2 across the superconducting phase transition. By changing the polarization of the Incoming Light, we were able to observe the opening of the gap for the inner hole pocket alpha and to compare its behavior with the outer holelike band beta. Measurements along high-symmetry directions show that the behavior of beta is consistent with an isotropic gap opening, while sLight anisotropies are detected for the inner band alpha. The implications of these results for the s +/- symmetry of the superconducting order parameter are discussed, in relation to the nature of the different iron orbitals contributing to the electronic structure of this multiband system.
