The Experts below are selected from a list of 218622 Experts worldwide ranked by ideXlab platform
H Ruhl - One of the best experts on this subject based on the ideXlab platform.
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high energy proton acceleration in interaction of short Laser Pulse with dense plasma target
Physics of Plasmas, 2003Co-Authors: Yasuhiko Sentoku, A J Kemp, T. E. Cowan, H RuhlAbstract:The generation of high energy protons from the interaction of a short Laser Pulse with a dense plasma, accompanied by a preformed low density plasma, has been studied by particle-in-cell simulations. The proton acceleration toward the Laser direction in the preformed plasma is characterized by a time-dependent model and the peak proton energy is given. The effect of electron recirculation on the rear side sheath acceleration is discussed and it is found that the peak proton energy increases in inverse proportion to the target thickness. These results shed light on the peak proton energy dependence on Laser intensity, Laser Pulse length, and target thickness. Finally the optimal parameters of the Laser Pulse for large ion peak energy and conversion efficiency are discussed.
Gary D. Noojin - One of the best experts on this subject based on the ideXlab platform.
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Ultrashort-Laser-Pulse retinal damage
Laser and Noncoherent Ocular Effects: Epidemiology Prevention and Treatment, 1997Co-Authors: Benjamin A. Rockwell, William P. Roach, Dale J. Payne, Paul K. Kennedy, Jeffrey J. Druessel, Rodney E. Amnotte, Brent Eilert, Shana L. Phillips, David J. Stolarski, Gary D. NoojinAbstract:Recent studies of retinal damage due to ultrashort Laser Pulses have shown that less energy is required for retinal damage for Pulses shorter than one nanosecond. Laser minimum visible lesion thresholds for retinal damage from ultrashort Laser Pulses are produced at lower energies than in the nanosecond to microsecond Laser Pulse regime. We review the progress made in determining the trends in retinal damage from Laser Pulses of one nanosecond to one hundred femtoseconds in the visible and near-infrared wavelength regimes. We have determined the most likely damage mechanism operative in this Pulse width regime and discuss implications on Laser safety standards.
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Histopathology of ultrashort-Laser-Pulse retinal damage
Laser-Tissue Interaction VII, 1996Co-Authors: Cynthia A. Toth, Benjamin A. Rockwell, William P. Roach, Rodney E. Amnotte, Gary D. Noojin, Drew G. Narayan, Catherine Osborne, Cindy D. Stein, Cheryl Dawn Dicarlo, Clarence P. CainAbstract:Recent studies of retinal damage due to ultrashort Laser Pulses have shown interesting behavior. Laser induced retinal damage for ultrashort (i.e. less than 1 ns) Laser Pulses is produced at lower energies than in the nanosecond to microsecond Laser Pulse regime and the energy required for hemorrhagic lesions is much greater times greater for the nanosecond regime. We investigated the tissue effects exhibited in histopathology of retinal tissues exposed to ultrashort Laser Pulses.
Wei-shen Zhan - One of the best experts on this subject based on the ideXlab platform.
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Field-free orientation of CO molecule by combining two-color femtosecond Laser Pulse with time-delayed positively chirped Laser Pulse
European Physical Journal D, 2018Co-Authors: Shuo Wang, Wei-shen Zhan, Hui-fang LiAbstract:The orientation of CO molecule controlled by two-color femtosecond Laser Pulse and positively chirped Laser Pulse is investigated theoretically. Compared with the single two-color or positively chirped Laser Pulse, the combination of two Laser Pulses with an optimized delay time can greatly improve the degrees of the positive and negative molecular orientation, respectively. The effects of intensity of two-color femtosecond Laser Pulse on molecular orientation are discussed, and the molecular orientation can be achieved by a calculated intensity. Additionally, the delay time between two-color femtosecond Laser Pulse and positively chirped Laser Pulse can significantly enhance the molecular orientation. Furthermore, by varying the carrier frequency and the chirp value of the positively chirped Laser Pulse, it is shown that the molecular orientation can be changed to some degree. The positive and negative molecular orientation can also be manipulated by adjusting the relative amplitude of the second harmonic field with respect to the fundamental.
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Field-free orientation dynamics of CO molecule by combining two-color shaped Laser Pulse with THz Laser Pulse train
Chemical Physics, 2015Co-Authors: Hai-ping Dang, Shuo Wang, Wei-shen ZhanAbstract:Abstract Field-free orientation of CO molecule is studied theoretically by combining a nonresonant two-color shaped Laser Pulse with a time-delayed THz Laser Pulse train. The molecular positive and negative orientation degrees can be significantly enhanced by the combination of two-color shaped Laser Pulse and THz Laser Pulse train compared with the single THz Laser Pulse train. The effects of the Pulse number of THz Laser Pulse train and the delay time between two-color shaped Laser Pulse and THz Laser Pulse train on molecular orientation are discussed. Further, the influence of the initial rotational temperature on molecular orientation is investigated. The maximal positive and negative orientation degrees obtained are 〈cos θ 〉 pmax = 0.91 and 〈cos θ 〉 nmax = 0.89, respectively.
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Field-free molecular orientation by two-color femtosecond Laser Pulse and time-delayed THz Laser Pulse
Laser Physics, 2015Co-Authors: Hai-ping Dang, Shuo Wang, Wei-shen ZhanAbstract:We propose a scheme for achieving molecular orientation steered by the combination of a nonresonant two-color femtosecond Laser Pulse and a time-delayed THz Laser Pulse. It is shown that the molecular negative and positive orientation can be significantly enhanced by applying this scheme compared to the single femtosecond or THz Laser Pulse. The effects of the intensity of the two-color femtosecond Laser Pulse and the delay time between the femtosecond Laser Pulse and the THz Laser Pulse on molecular orientation are discussed. The molecular orientation also depends on the carrier-envelope phase of the THz Laser Pulse and the initial rotational temperature of the molecule. The maximal negative and positive orientation degrees calculated are and , respectively.
Feng Chen - One of the best experts on this subject based on the ideXlab platform.
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Multi-Frame Observation of a Single Femtosecond Laser Pulse Propagation Using an Echelon and Optical Polarigraphy Technique
IEEE Photonics Technology Letters, 2013Co-Authors: Xiaofang Wang, Jinhai Si, Pengchao He, Feng ChenAbstract:We developed a multiframe observation method of femtosecond Laser Pulse propagating in transparent medium based on optical polarigraphy technique. An echelon was introduced into the probe light and divided it into multiPulses both in time and space, allowing a multiframe detection of the intense Laser Pulse propagating in materials. Using this method, we realized a multiframe observation of a single femtosecond Laser Pulse propagating in CS2 with ultrafast self-modulation such as filamentation. This imaging method has been demonstrated to be of a femtosecond time resolution and a frame rate of ~ THz.
Philippe Delaporte - One of the best experts on this subject based on the ideXlab platform.
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Influence of Laser Pulse shape on dry Laser cleaning
Applied Surface Science, 2006Co-Authors: David Grojo, M. BoyoMo-Onana, Alain Cros, Philippe DelaporteAbstract:The influence of Laser Pulse shape and Pulse duration on dry Laser cleaning is investigated by means of combined experimental and theoretical approaches. Possibilities to enhance damage-free particle removal efficiency by adjusting the temporal parameters of Laser irradiations are discussed. The numerical description predicts that the removal of sub-micron particles by excimer Lasers occurs in the 'quasi-static' inertia force regime. Experiments are based on an electro-optic gating system capable of switching off either leading or trailing edges of an excimer Laser Pulse. It is demonstrated that the inertia force corresponding to the Pulse trailing front may play a role in Laser cleaning but not as the dominant mechanism. Both the surface temperature and the expansion dynamics of materials are calculated in order to examine their role in dry Laser cleaning. This study helps to determine the dominant mechanism responsible for particle removal by nanosecond Laser Pulses. ?? 2005 Elsevier B.V. All rights reserved.
