The Experts below are selected from a list of 24315 Experts worldwide ranked by ideXlab platform
V.p. Kandidov - One of the best experts on this subject based on the ideXlab platform.
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Light bullets and supercontinuum spectrum during Femtosecond Pulse filamentation under conditions of anomalous group-velocity dispersion in fused silicalicati
Quantum Electronics, 2013Co-Authors: S V Chekalin, V O Kompanets, E.o. Smetanina, V.p. KandidovAbstract:We report the results of theoretical and experimental research on spectrum transformation and spatiotemporal distribution of the Femtosecond Laser radiation intensity during filamentation in fused silica. The formation of light bullets with a high power density is first observed in a Femtosecond Laser Pulse in the anomalous group velocity dispersion regime at a wavelength of 1800 nm. The minimum duration of the light bullet is about two oscillation cycles of the light field.
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from self focusing light beams to Femtosecond Laser Pulse filamentation
Physics-Uspekhi, 2013Co-Authors: S V Chekalin, V.p. KandidovAbstract:2012 marked the 50th anniversary of the first published prediction of the self-focusing phenomenon in light beams. The recent revived interest in the subject is due to advances in high-power Femtosecond Laser technology and due to the possibility they provided of creating extended filaments of high light field intensity in gases and condensed media. This review shows in retrospect how our understanding of the self-action of light evolved from the self-focusing of Laser beams in the 1960s to the filamentation of Femtosecond Laser Pulses at present. We also describe the current status of this rapidly growing area of nonlinear optics and Laser physics. Finally, we discuss, in general terms, what the phenomena of Laser beam self-focusing and Laser Pulse filamentation have in common and how they differ.
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the propagation of powerful Femtosecond Laser Pulses in opticalmedia physics applications and new challenges
Canadian Journal of Physics, 2005Co-Authors: S L Chin, O G Kosareva, Neset Akozbek, V.p. Kandidov, Andreas Becker, Weiwei Liu, S A Hosseini, Q Luo, F Theberge, Hartmut SchroederAbstract:When a powerful Femtosecond Laser Pulse propagates in an optical medium, self-focusing occurs. Normally, it is the most powerful part (slice) of the Pulse that self-focuses first during its propaga...
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self transformation of a powerful Femtosecond Laser Pulse into a white light Laser Pulse in bulk optical media or supercontinuum generation
Applied Physics B, 2003Co-Authors: V.p. Kandidov, C M Bowden, O G Kosareva, Neset Akozbek, I.s. Golubtsov, A. Becker, S L ChinAbstract:We present experimental and theoretical results on white-light generation in the filamentation of a high-power Femtosecond Laser Pulse in water and atmospheric air. We have shown that the high spatio-temporal localization of the light field in the filament, which enables the supercontinuum generation, is sustained due to the dynamic transformation of the light field on the whole transverse scale of the beam, including its edges. We found that the sources of the supercontinuum blue wing are in the rings, surrounding the filament, as well as at the back of the Pulse, where shock-wave formation enhanced by self-steepening takes place. We report on the first observation and demonstration of the interference of the supercontinuum spectral components arising in the course of multiple filamentation in a terawatt Laser Pulse. We demonstrate that the conversion efficiency of an initially narrow Laser Pulse spectrum into the supercontinuum depends on the length of the filament with high intensity gradients and can be increased by introducing an initial chirp.
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Femtosecond Laser Pulse filamentation versus optical breakdown in h2o
Applied Physics B, 2003Co-Authors: O G Kosareva, I.s. Golubtsov, V.p. Kandidov, Andreas Becker, A Iwasaki, S L ChinAbstract:The competition between Femtosecond Laser Pulse induced optical breakdown and Femtosecond Laser Pulse filamentation in condensed matter is studied both experimentally and numerically using water as an example. The coexistence of filamentation and breakdown is observed under tight focusing conditions. The development of the filamentation process from the creation of a single filament to the formation of many filaments at higher Pulse energy is characterized systematically. In addition, strong deflection and modulation of the supercontinuum is observed. They manifest themselves at the beginning of the filamentation process, near the highly disordered plasma created by optical breakdown at the geometrical focus.
Shuji Sakabe - One of the best experts on this subject based on the ideXlab platform.
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Laser fluence dependence of periodic grating structures formed on metal surfaces under Femtosecond Laser Pulse irradiation
Physical Review B, 2010Co-Authors: Kiminori Okamuro, Yasuhiro Miyasaka, Masaki Hashida, Shigeki Tokita, Yoshinobu Ikuta, Shuji SakabeAbstract:Periodic structures self-formed on the surface of several metals under Femtosecond Laser-Pulse irradiation are investigated by electron microscopy. For the self-formation of periodic gratings on metal surfaces, the interspaces of the periodic structures depend on Laser fluence. This dependence is the same for all metals, although the range of Laser fluence in which the structures are formed differs between metals. The Laser fluence dependence can be explained by the generation of a plasma wave through the parametric decay of Laser light [S. Sakabe, M. Hashida, S. Tokita, S. Namba, and K. Okamuro, Phys. Rev. B 79, 033409 (2009)]. This indicates that the formation of periodic structures depends not only on metal properties but also on the electron density of plasma produced on a surface by Femtosecond Laser Pulses.
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mechanism for self formation of periodic grating structures on a metal surface by a Femtosecond Laser Pulse
Physical Review B, 2009Co-Authors: Shuji Sakabe, Masaki Hashida, Shigeki Tokita, Shin Namba, Kiminori OkamuroAbstract:Periodic grating structures self-formed on a metal surface under the irradiation of a Femtosecond Laser Pulse are characterized by grating spaces which are shorter than the Laser wavelength, as well as by dependence on the Laser fluence. This Brief Report presents a different interpretation of these features in terms of the process of parametric decay of Laser light to surface plasma waves. Depending on the electron density, grating spaces with lengths of 680 nm to as short as 400 nm can be produced for 800 nm Laser wavelength as a result of the interaction of Laser Pulses with Laser-produced surface plasma.
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anisotropic coulomb explosion of c60 irradiated with a high intensity Femtosecond Laser Pulse
Journal of Chemical Physics, 2000Co-Authors: Junkei Kou, Shuji Sakabe, Masaki Hashida, V V Zhakhovskii, Katsunobu Nishihara, Seiji Shimizu, Sakae Kawato, Keisuke Shimizu, Sergei V Bulanov, Yasukazu IzawaAbstract:C60 vapor was irradiated with an intense Femtosecond Laser Pulse (1×1016 W/cm2 in 120 fs at a wavelength of 800 nm). Multiply charged carbon ions, up to C4+, were detected in the time-of-flight spectra. We have measured both energy and angular distributions with respect to the Laser polarization direction for ions with different charge number. The kinetic energy of ions are distributed above 1 keV. The angular distribution measurement shows that the highly charged ions of C3+ and C4+ are mostly distributed in the directions parallel to the Laser polarization, and the C+ ions are slightly distributed in the direction perpendicular to it. These observations clearly indicate that an anisotropic explosion takes place. The average energy of ions with the different charge number is found to be proportional to the square of the charge number, while the maximum energy is proportional to the charge number. Classical molecular dynamics simulations have been successfully carried out reproducing not only the energy s...
Howard Milchberg - One of the best experts on this subject based on the ideXlab platform.
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Full path single-shot imaging of Femtosecond Pulse collapse in air turbulence
Optics letters, 2020Co-Authors: Ilia Larkin, J. Griff-mcmahon, Aaron Schweinsberg, A. Goffin, Anthony Valenzuela, Howard MilchbergAbstract:In a single shot, we measure the full propagation path, including the evolution to Pulse collapse, of a high power Femtosecond Laser Pulse propagating in air. Our technique enables examination of the effect of parameters that fluctuate on a shot-to-shot basis, such as Pulse energy, Pulse duration, and air turbulence-induced refractive index perturbations. We find that even in lab air over relatively short propagation distances, turbulence plays a significant role in determining the location of Pulse collapse.
Kiminori Okamuro - One of the best experts on this subject based on the ideXlab platform.
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Laser fluence dependence of periodic grating structures formed on metal surfaces under Femtosecond Laser Pulse irradiation
Physical Review B, 2010Co-Authors: Kiminori Okamuro, Yasuhiro Miyasaka, Masaki Hashida, Shigeki Tokita, Yoshinobu Ikuta, Shuji SakabeAbstract:Periodic structures self-formed on the surface of several metals under Femtosecond Laser-Pulse irradiation are investigated by electron microscopy. For the self-formation of periodic gratings on metal surfaces, the interspaces of the periodic structures depend on Laser fluence. This dependence is the same for all metals, although the range of Laser fluence in which the structures are formed differs between metals. The Laser fluence dependence can be explained by the generation of a plasma wave through the parametric decay of Laser light [S. Sakabe, M. Hashida, S. Tokita, S. Namba, and K. Okamuro, Phys. Rev. B 79, 033409 (2009)]. This indicates that the formation of periodic structures depends not only on metal properties but also on the electron density of plasma produced on a surface by Femtosecond Laser Pulses.
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mechanism for self formation of periodic grating structures on a metal surface by a Femtosecond Laser Pulse
Physical Review B, 2009Co-Authors: Shuji Sakabe, Masaki Hashida, Shigeki Tokita, Shin Namba, Kiminori OkamuroAbstract:Periodic grating structures self-formed on a metal surface under the irradiation of a Femtosecond Laser Pulse are characterized by grating spaces which are shorter than the Laser wavelength, as well as by dependence on the Laser fluence. This Brief Report presents a different interpretation of these features in terms of the process of parametric decay of Laser light to surface plasma waves. Depending on the electron density, grating spaces with lengths of 680 nm to as short as 400 nm can be produced for 800 nm Laser wavelength as a result of the interaction of Laser Pulses with Laser-produced surface plasma.
Armand Beche - One of the best experts on this subject based on the ideXlab platform.
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single Femtosecond Laser Pulse excitation of individual cobalt nanoparticles
Physical Review B, 2020Co-Authors: Tatiana Savchenko, M Buzzi, Ludovic Howald, Sergiu Ruta, Jaianth Vijayakumar, Martin Timm, David Bracher, Susmita Saha, P M Derlet, Armand BecheAbstract:The interaction of light and magnetism at the nanoscale is a topic of fundamental interest with potential impact on future spintronics applications. This work addresses theoretically and experimentally the effect of Femtosecond Laser Pulse excitation on the magnetic, structural, and chemical stability of individual magnetic cobalt nanoparticles, including the role of the substrate or matrix. Based on their results, the authors discuss possible pathways to achieve Laser-induced magnetic switching in individual nanostructures.