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Simulation of the Quasi-Monoenergetic Protons Generation by Parallel laser pulses Interaction with Foils

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Chinese Physics Letters 2014年第11期31卷 103-106页

作者：王伟权银燕邹德滨余同普徐涵郁明阳马燕云 College of Science National University of Defense Technology Changsha 410073 College of Computer Science National University of Defense Technology Changsha 410073 Institute for Fusion Theory and Simulation Zhejiang University Hangzhou 310027

A new scheme of radiation pressure acceleration for generating high-quality protons by using two overlappingparallel laser pulses is proposed. Particle-in-cell simulation shows that the overlapping of two pulses with identical Caussian profiles in space and trapezoidal profiles in the time domain can result in a composite light pulse with a spatial profile suitable for stable acceleration of protons to high energies. At～2.46 × 10^21 W/cm^2 intensity of the combination light pulse, a quasi-monoenergetic proton beam with peak energy ,～200 MeV/nucleon, energy spread 〈15%, and divergency angle 〈4° is obtained, which is appropriate for tumor therapy. The proton beam quality can be controlled by adjusting the incidence points of two laser pulses.

关键词： PROTONS laser pulses PROTON beams TUMOR treatment RADIATION pressure

Plasma channel formed by ultraviolet laser pulses at 193 nm in air

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Chinese Optics Letters 2009年第9期7卷 865-868页

作者：马媛媛鲁欣奚婷婷龚旗煌张杰 State Key Laboratory for Mesoscopic Physics Department of PhysicsPeking University Laboratory of Optical Physics Institute of PhysicsChinese Academy of Sciences Department of Physics Graduate University of Chinese Academy of Sciences Department of Physics Shanghai Jiao Tong University

The propagation of picosecond deep ultraviolet laser pulse at wavelength of 193 nm in air is numerically investigated. Long plasma channel can be formed due to the competition between Kerr self-focusing and ionization induced defocusing. The plasma channel with electron density of above 10^13/cm^3 can be formed over 70 m by 50-ps, 20-mJ laser pulses. The fluctuation of laser intensity and electron density inside ultraviolet （UV） plasma channel is significantly lower UV laser by air is considered in the simulation and it the limit of the length of plasma channel. than that of infrared pulse. The linear absorption of is shown that the linear absorption is important for the limit of the length of plasma channel.

关键词： Absorption Carrier concentration Electron density measurement Electrons laser pulses lasers Plasmas

Experimental study on multiphoton ionization of Ar with high intensity short laser pulses

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Chinese Optics Letters 2010年第3期8卷 338-341页

作者：张晓吟全威王阳康会鹏刘红平柳晓军 State Key Laboratory of Magnetic Resonance and Atomic and Molecular PhysicsWuhan Institute of Physics and Mathematics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

We present high resolution photoelectron energy spectra from multiphoton ionization （MPI） of Ar subject to laser pulses with wavelength of 400 nm, pulse duration of 35 fs, and maximum intensity of 5×10^13 W/cm2. Ionizations into Ar＋ 2p3/2 and 2P1/2 channels are observed and distinct resonance structures are found in both ionization channels. The intensity dependence of the resonance structures is explained in terms of the mechanism of Freeman resonance, i.e., transient resonances of alternating current （AC） Stark-shifted Rydberg states at specific intensities within the laser pulse.

关键词： laser pulses Particle detectors Photoelectron spectroscopy Photoionization Resonance Spectroscopy

Measuring Carrier-Envelope Phase of Few-Cycle laser pulses Using High-Order Above-Threshold Ionization Photoelectrons

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Chinese Physics Letters 2014年第6期31卷 117-120页

作者：邓勇开黎敏于济州刘院省刘运全龚旗煌 Department of Physics and State Key Laboratory for Mesoscopic Physics Peking University Beijing 100871 Collaborative Innovation Center of Quantum Matter Beijing 100871

We experimentally demonstrate the measurement of carrier-envelope phase of few-cycle laser pulses. We have built a stereo above-threshold ionization setup. The photoelectron energy spectra of high-order above-threshold ionization are measured in both the left and right directions in the linearly polarized laser fields. It is shown that the left-right asymmetry of the spectra is dependent on carrier-envelope phase of few-cycle laser pulses. Two asymmetry parameters from the low-energy and high-energy regions at the above-threshold ionization plateau map a phase ellipse, in which the points indicate the absolute value of carrier-envelope phase. We have calibrated the phase ellipse by comparison with the semiclassical calculation. This setup allows us to determine the value of the absolute phase of few-cycle laser pulses.

关键词： laser pulses IONIZATION (Atomic physics) PHOTOELECTRONS RESEARCH ASYMMETRY (Chemistry) PHOTOELECTRON spectrometers PHOTOELECTRON spectra

Quasi-Monoenergetic Electron Beam Generation from Nanothickness Solid Foils Irradiated by Circular-Polarization laser pulses

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Chinese Physics Letters 2014年第7期31卷 132-136页

作者：苏恒毅黄永盛王乃彦汤秀章鲁巍 High Power Excimer laser Laboratory China Institute of Atomic Energy Beijing 102413 Department of Engineering Physics Tsinghua University Beijing 100084

Ultrashort 10^22-10^24 W/cm^2 laser pulses will offer the possibility of producing monoenergetic electron beams in the Ge V - Te V level in the future. A laser-electron acceleration scheme is proposed by the interaction between a thin solid foil and an ultra-intense laser pulse for a0 ≥ 800σ0, where ao is the normalized laser field and σ0 is the normalized plasma surface density. The energy of the electrons as a function of time can be described by a simple model which indicates that an exponential relationship exists between the energy and the normalized time τ. A quasi-monoenergetic high density electron beam with 1.3 Ge V energy and a 2.2% energy spread has been predicted for a0 = 223.5 by particle-in-cell simulations. Characteristics of the ultra-high density electron layer formed in the early period of the acceleration are discussed.

关键词： ELECTRON beams MONOENERGETIC radiation laser pulses PLASMA density ELECTRON accelerators

Generation of synchronized femtosecond and picosecond laser pulses in a two-beam-pumped Ti:sapphire laser

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Chinese Optics Letters 2010年第2期8卷 194-196页

作者：朱长军贺俊芳翟学军薛兵张崇辉 Department of Physics School of ScienceXi'an Polytechnic University State Key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision MechanicsChinese Academy of Sciences

Two operating modes, independent self-mode-locking and cross-mode-locking, are presented in a two-beam- pumped double-cavity dual-wavelength femtosecond Ti：sapphire laser. Synchronization of femtosecond and picosecond laser pulses is achieved by properly adjusting the cavity length matching and distributing the pump laser powers in the two laser cavities, and moreover, a timing jitter of 517 fs between femtosecond and picosecond pulses is obtained, with wavelength tuning ranges around 36 and 22 nm in the femtosecond and picosecond cavities, respectivelv.

关键词： laser pulses Pulsed laser applications Pumping (laser) Sapphire Timing jitter

The Hyperbolic Two Temperature Semiconducting Thermoelastic Waves by laser pulses

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Computers, Materials & Continua 2021年第6期67卷 3601-3618页

作者： Ismail M.Taye Kh.Lotfy A.A.El-Bary Jawdat Alebraheem Sadia Asad Department of Mathematics College of Science Al-ZulfiMajmaah University11952Saudi Arabia Department of Mathematics Faculty of ScienceZagazig UniversityZagazigEgyp t 3Arab Academy for Science Technology and Maritime TransportAlexandriaEgypt Department of Mathematics Faculty of ScienceTaibah UniversityMadinahSaudi Arabia National Committee for Mathematics Academy of Scientific Research and TechnologyCairoEgypt

A novel model of a hyperbolic two-temperature theory is investigated to study the propagation the thermoelastic waves on semiconductor *** governing equations are studied during the photo-excitation processes in the context of the photothermal *** outer surface of o semiconductor medium is illuminated by a laser *** generalized photo-thermoelasticity theory in two dimensions(2D)deformation is used in many models(Lord–Shulman(LS),Green–Lindsay(GL)and the classical dynamical coupled theory(CD)).The combinations processes between the hyperbolic two-temperature theory and photo-thermoelasticity theory under the effect of laser pulses are obtained *** harmonic wave technique is used to obtain the exact solutions of the main physical fields under *** mechanical,thermal and recombination plasma loads are applied at the free surface of the medium to obtain the complete solutions of the basic physical *** comparisons are made between the three thermoelastcity theories under the electrical effect of thermoelectric coupling *** influence of hyperbolic two-temperature,two-temperature and one temperature parameters on the distributions of wave propagation of physical fields for semiconductor silicon(Si)medium is shown graphically and discussed.

关键词： Photo-thermo-elasticity theory semiconductors laser pulses hyperbolic two temperature harmonic waves thermo-elastic waves

High-order harmonics in static gas target by 795-nm Ti:sapphire femtosecond laser pulses

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Chinese Optics Letters 2004年第3期2卷 182-184页

作者：夏元钦陈德应陈建新王骐 Research Institute of Opto-Electronic Technology National Key Laboratory of Tunable Laser Technology Harbin Institute of Technology Harbin 150001

The 5th -23sd high-order harmonics generation in rare gases in static gas target with 120-fs, 85-mJ/pulse, 10-Hz laser system was investigated. Compared with the traditional gas target, static gas target is simple to be used in experiment, and the experimental parameters can be easily controlled. The effects on high-order harmonics due to laser intensities (energy), polarization, gas densities, confocal parameter, and phase mismatch were studied in this paper.

关键词： Inert gases laser pulses

Coherent population transfer with chirped few-cycle laser pulses in an excited-doublet four-level system

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Chinese Optics Letters 2005年第8期3卷 435-437页

作者：杨玮枫龚尚庆钮月萍徐至展 State Key Laboratory of High Field laser Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences Beijing 100039 The behavior of population transfer in an excited-doublet four-level system driven by linear polarized few-cycle ultrashort laser pulses is investigated numerically. It is shown that almost complete population transfer can be achieved even when the adiabatic criterion is not fulfilled. Moreover the robustness of this scheme in terms of the Rabi frequencies and chirp rates of the pulses is explored

The behavior of population transfcr in an excited-doublet four-level system driven by linear polarized few-cycle ultrashort laser pulses is investigated numerically. It is shown that almost complete population transfer can be achieved even when the adiabatic criterion is not fulfilled. Moreover, the robustness of this scheme in terms of the Rabi frequencies and chirp rates of the pulses is explored.

关键词： Electron transitions laser pulses Pulsed laser applications Ultrashort pulses