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1.
This review contains theoretical study of resonant quantum electrodynamics processes in a pulsed laser field. The approximation is examined when the pulse width is considerably greater than the characteristic time of wave oscillations. The lepton??s interaction with the Coulomb potential of a nucleus and each other is considered in the Born approximation. It is demonstrated that the resonant differential cross section of a process in a pulsed light fields may considerably exceed the corresponding cross section in an absence of a laser field. Results obtained may be experimentally verified by the scientific facilities at the SLAC National Accelerator Laboratory and FAIR (Facility for Antiproton and Ion Research, Darmstadt, Germany) project. 相似文献
2.
The resonant photoproduction of an electron-positron pair on a nucleus in the field of a pulsed light wave is studied theoretically.
The approximation where the electromagnetic pulse duration is much longer than the characteristic time of wave oscillations
is considered. The interaction of the electron and positron with the Coulomb potential of the nucleus is considered in the
Born approximation. An analytical expression for the resonant differential cross section is derived for the range of moderately
strong external fields. This cross section contains a resonant peak whose height and width are determined by the external
pulsed wave characteristics. The resonant cross section for pair photoproduction on a nucleus in a pulsed laser field can
exceed the corresponding cross section for pair photoproduction on a nucleus in the absence of an external field by an order
of magnitude. 相似文献
3.
Nonresonant photocreation of electron-positron pair on a nucleus in the field of a pulsed light wave
The nonresonant Coulomb photocreation of electron-positron pair on a nucleus in the field of a pulsed light wave is theoretically
investigated. The approximation is examined when pulsewidth is considerably greater than the characteristic time of wave oscillations.
The interaction of an electron and a positron with a Coulomb potential of a nucleus is considered in the first order of perturbation
theory (the Born approximation). An analytic expression for the nonresonant differential cross section was obtained for the
range of moderately strong fields in the case relativistic and nonrelativistic energies. It is shown, that the nonresonant
cross section of Coulomb photocreation of nonrelativistic pair in the field of a pulsed light wave is two times larger than
the cross section of Coulomb photocreation in the absence of an external field. 相似文献
4.
The scattering of an electron by a muon in the presence of a linearly polarized laser field is investigated in the first Born approximation. The theoretical results reveal the following: i) At medium and large scattering angles, many multiphoton processes occur during scattering, and these nonlinear phenomena may predict the resonant state of the electron and the muon formed in the collision process. ii) The photoabsorption (inverse bremsstrahlung) dominates the photoemission (bremsstrahlung), causing the cross section to increase. iii) When the laser polarization deviates from the incident direction, the lasermodified total cross section depends considerably on the azimuthal angle of the scattered electron. The dependence of the cross section on the field strength, polarization direction, and electron-impact energy are studied. 相似文献
5.
根据光的吸收机理,分析了单粒子效应脉冲激光模拟实验中所需用的脉冲激光的特点,探讨了脉冲激光单粒子效应的Monte Carlo计算模拟途径。在只考虑光电效应的简化下,得到存储器硅片单粒子翻转时入射脉冲激光能量阈值与临界电荷的计算关系式,进而给出该硅片的翻转截面的计算公式。在给定了存储器硅片的临界电荷的情况下,对入射脉冲激光能量阈值和单粒子翻转截面进行了计算。 相似文献
6.
Bragg acoustooptic diffraction of nanosecond pulsed laser radiation from a frequency- and/or phase-keyed acoustic wave is
studied experimentally and theoretically for exact synchronization of laser pulses and signal keying. It is shown that the
diffraction field for short pulses is practically stationary and is determined by the positions of acoustic signal keying
over signal aperture. The application of this type of signals for the formation of a multibeam diffraction pulsed radiation
field is considered. A method is proposed for transforming the angular spectrum of laser radiation intensity from the initial
Gaussian to a nearly rectangular spectrum. This may considerably increase the efficiency of high-power technological lasers
used in material processing (laser cutting, welding, engraving, etc.), in which the action of radiation is of the thresh-old
type in light intensity. The possibility of correcting the angular intensity distribution for a pulsed fiber laser, which
increases the thermal efficiency of radiation from such a laser, is established experimentally. 相似文献
7.
The process of resonant scattering of a lepton by a lepton in the field of pulsed light wave in general relativistic case
is studied theoretically. The approximation when a pulsewidth is considerably greater than the characteristic time of wave
oscillation is considered. The analytical expression for the resonant differential cross-section of concerned process is derived
within the framework of the first order of the perturbation theory with respect to external laser field; it contains the resonant
peak, the altitude and the width of which are defined by the external pulsed wave characteristics. It is demonstrated, that
the resonant differential cross-section of scattering of an electron by an electron (an electron by a positron, an electron
by a muon) in the pulsed light field may be several orders of magnitude greater than the corresponding one in the external
field absence. The derived results may be verified experimentally for example by scientific facility at SLAC National Accelerator
Laboratory. 相似文献
8.
在量子散射框架下,对真实激光场引进多光子相互作用准静态过程模型,考虑束缚-自由跃迁中电磁场的规范一致性及电子与激光场长程相互作用的极限,研究激光场对量子散射过程中三重微分散射截面的影响.多数共面非对称情况下激光场对三重微分散射截面有提升作用,此外靶原子处于激发态时binary峰出现分裂,激光场对三重微分散射截面也有放大作用. 相似文献
9.
在量子散射框架下,对真实激光场引进多光子相互作用准静态过程模型,考虑束缚-自由跃迁中电磁场的规范一致性及电子与激光场长程相互作用的极限,研究激光场对量子散射过程中三重微分散射截面的影响。多数共面非对称情况下激光场对三重微分散射截面有提升作用,此外靶原子处于激发态时binary峰出现分裂,激光场对三重微分散射截面也有放大作用。 相似文献
10.
The scattering of a plane electromagnetic wave by 2D nanoparticles is simulated using the boundary integral equation method. The accuracy and smoothness of the solution are improved by applying Hermitean interpolants for discretization. The accuracy of the numerical approach used in this paper is comparable to the Mie classical solution for scattering by a circular cylinder. It is shown that laser radiation incident on silver nanoparticles generates plasma resonances, giving rise to peak values of the extinction cross section and considerably enhancing the local electromagnetic field on the surface. 相似文献
11.
Theoreticalanalysisandexperimentalinvestigationofpulsedtunableforsteritelaser¥WUFushun;WUXing;B.Hamilton;YAOJianquan(PhysicsD... 相似文献
12.
A four-state model considering the relative velocity distribution function for calculating the cross section of laserinduced collisional energy transfer in a Sr-Li system is presented and profiles of laser-induced collision cross section are obtained.The resulting spectra obtained from different intermediate states are strongly asymmetrical in an opposite asymmetry.Both of the two intermediate states have contributions to the final state,and none of the intermediate states should be neglected.The peak of the laser-induced collisional energy transfer(LICET) profile shifts toward the red and the FWHM becomes narrower obviously with laser field intensity increasing.A cross section of 1.2 × 10-12 cm 2 at a laser field intensity of 2.17 × 10 7 V/m is obtained,which indicates that this collision process can be an effective way to transfer energy selectively from a storage state to a target state.The existence of saturation for cross section with the increase of the laser intensity shows that the high-intensity redistribution of transition probabilities is an important feature of this process,which is not accounted for in a two-state treatment. 相似文献
13.
14.
Two-photon absorption(2PA) in zinc sulphide(ZnS) and Mn2+-doped ZnS quantum dots is reported by the z-scan technique,with nanosecond pulsed laser radiation at 355 nm.The observed values of the 2PA cross section of all the samples are 105 times larger than that of bulk ZnS. 相似文献
15.
Relativistic electron scattering from freely movable proton/μ~+ in the presence of strong laser field 下载免费PDF全文
《中国物理 B》2019,(9)
We have investigated the electron scattering from the freely movable spin-1/2 particle in the presence of a linearly polarized laser field in the first Born approximation.The laser-dressed state of electrons is described by a time-dependent wave function which is derived from a perturbation treatment.With the aids of numerical simulations, we explore the dependencies of the differential cross section on the laser field intensity as well as the electron-impact energy.Due to the mobility of the target, the differential cross section of this process is smaller than that of Mott scattering. 相似文献
16.
The propagation of a spikelike ultrashort laser pulse in a mirror waveguide of rectangular cross section with perfectly conducting walls is considered. An algorithm for the calculation of the propagation of a field pulse in such a waveguide is designed. The general approach is illustrated by calculation of the propagation of a p-polarized field pulse shorter than the dimensions of the waveguide cross section. 相似文献
17.
We present a novel technique to fabricate deeply embedded microelectrodes in LiNbO3 using femtosecond pulsed laser ablation and selective electroless plating. The fabrication process mainly consists of four steps, which are (1) micromachining of microgrooves on the surface of LiNbO3 by femtosecond laser ablation; (2) formation of AgNO3 films on substrates; (3) scanning the femtosecond laser beam in the fabricated microgrooves for modification of the inner surfaces; and (4) electroless copper plating. The void-free electroless copper plating is obtained with appropriate cross section of microgrooves and uniform initiation of the autocatalytic deposition on the inner surface of grooves. The dimension and shape of the microelectrodes could be accurately controlled by changing the conditions of femtosecond laser ablation, which in turn can control the distribution of electric field inside LiNbO3 crystal for various applications, opening up a new approach to fabricate three-dimensional integrated electro-optic devices. 相似文献
18.
A. Makhoute D. Khalil 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(1):77-82
We study electron-atom scattering in the presence of a
laser field with elliptic polarization. We discuss the dependence
of the differential cross sections for the cases of circular and
linear polarizations as a function of scattering angle.
Interesting typical signatures of the phase between the two
components of the circular polarization of the laser field appear
in the differential cross section. 相似文献
19.
本文采用最小二乘法对空间域相位调制形成的干涉场的采样数据进行处理,给出了测量干涉场特征量的数学处理方法,分析测量相位和位移的误差,指出激光束截面强度的非均匀性会给测量带来系统误差,最后提出一种以偶然误差替换这一系统误差的数学物理理想。 相似文献
20.
Shin-ichi Satake Tomoaki Kunugi Kazuho Sato Tomoyoshi Ito Jun Taniguchi 《Optical Review》2005,12(6):442-444
A micro digital-holographic particle-tracking velocimetry (micro-DHPTV) method for high time-resolution flow field measurement
in a micro-channel is developed. The system consists of an objective lens, a high-speed camera and a single high-frequency
double pulsed laser. Particle positions in a three-dimensional field can be reconstructed by a computer-generated hologram.
The time evolution of a three-dimensional water flow in a semicircular micro-channel of 100-μm width and 40-μm depth is obtained
successfully using this micro-DHPTV system. The three-dimensional measurement volume of the system is 410 × 100 × 40 μm3 and is irradiated by one laser beam with the time resolution of 100 μs and a reputation rate of 1 kHz. Consequently, 130
velocity vectors in the semicircular micro-channel can be obtained instantaneously. A significant aspect of this method is
that even though both the laser and camera are located in line and perpendicular to the flow direction, velocity vectors can
be obtained by reconstructing the particle positions via the computer hologram and the semicircular cross section shape of
the micro-channel can be resolved. 相似文献