The exact solution of the relativistic equation of motion of acharged particle driven by an elliptically polarized electromagneticwave

An exact solution of the relativistic equation of motion of a charged particle driven by an elliptically polarized electromagnetic wave is obtained. The method used for this purpose is simple, and the results of earlier authors for the linearly and circularly polarized waves can be recovered as special cases of the solution     

Relativistic ponderomotive forces in the field of intense laser radiation

The motion of a relativistic charged particle in the presence of the field of high-power laser radiation represented in the form of a Gaussian beam of arbitrary mode is analyzed. The vector potential of the radiation field is expanded in terms of a small parameter (the ratio of the wavelength to the Gaussian beam waist). A specific feature of averaging with respect to the phases of the high-mode Gaussian beams is demonstrated. The averaged equations for the motion of particle and a general expression for the ponderomotive relativistic force for the circularly polarized radiation are derived. It is demonstrated that relativistic effects suppress the averaged action of high-power laser radiation on the particle.     

Multiple scattering of polarized light in a turbid medium

It is shown that multiple scattering of polarized light in a turbid medium can be represented as independent propagation of three basic modes: intensity and linearly and circularly polarized modes. Weak interaction between the basic modes can be described by perturbation theory and gives rise to “overtones” (additional polarization modes). Transport equations for the basic and additional modes are derived from a vector radiative transfer equation. Analytical solutions to these equations are found in the practically important cases of diffusive light propagation and small-angle multiple scattering. The results obtained are in good agreement with experimental and numerical results and provide an explanation for the experimentally observed difference in depolarization between linearly and circularly polarized waves.     

Motion of a classical charged particle with spin in the external field of a plane electromagnetic wave

We obtain the solution to the equations of motion for a classical particle with spin, electric and magnetic charges, and electric and magnetic normal and anomalous moments, in the field of a plane electromagnetic wave. An explicit form of the solution is given for linearly polarized waves and monochromatic circularly polarized waves. The possibility is noted that due to the presence of the moments, the particle can be accelerated to speeds arbitrarily close to the speed of light.Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Fizika, No. 11, pp. 71–74, November, 1981.     

Cartesian Ovals as Phase Trajectories of Relativistic Charged Particles

For a relativistic charged particle interacting with a circularly polarized stationary electromagnetic wave running along a uniform magnetostatic field, it is shown that the plane on which the set of trajectories of the particle coincides with a set of Cartesian ovals can serve as a phase space, provided that certain conditions are fulfilled. The cases of both decelerated and accelerated waves are investigated, and the results obtained confirm the statement that the mentioned plane is the most natural phase surface for a particle in the system of fields under consideration.     

Kinetics of atoms in the field produced by elliptically polarized waves

The kinetics of atoms with degenerate energy levels in the field produced by elliptically polarized waves is considered in the semiclassical approximation. Analytic expressions for the force acting on an atom and for the diffusion coefficient in the momentum space are derived for the optical transition J _g =1/2→J _e = 1/2 in the slow atom approximation. These expressions are valid for an arbitrary one-dimensional configuration of the light field and for an arbitrary intensity. The peculiarities of the atomic kinetics are investigated in detail; these peculiarities are associated with ellipticity of light waves and are absent in particular configurations formed by circularly or linearly polarized waves, which were considered earlier.     

二维宽带相位梯度超表面设计及实验验证

针对圆极化波, 通过同极化反射超表面结构单元的空间排布, 设计实现了一种二维非色散高效相位梯度超表面. 同极化反射相位可以通过同极化反射超表面结构单元金属线的面内旋转来自由调控. 实现的相位梯度超表面可对左右旋入射波产生相反的相位梯度. 当线极化波入射到超表面上时, 反射波被分为两束向相反方向传播的圆极化波. 仿真了线极化波垂直入射时的反射功率密度谱, 仿真结果与理论上设计的异常反射方向一致. 制作了厚度为2 mm的超表面样品, 测试了其镜面反射率曲线. 实验结果表明, 线极化波垂直入射时, 超表面在9.5-19.0 GHz的镜面反射率降至-5 dB以下.     

An exact solution of the relativistic equation of motion of acharged particle driven by a circularly polarized electromagnetic waveand a constant magnetic field

An exact solution is found for the relativistic equation of motion of a charged particle driven by a circularly polarized electromagnetic wave and a constant magnetic field. The explicit expressions of particle position and velocity are obtained for certain initial conditions. The results are of interest to the interaction of the high-power laser with the magnetized plasma, electromagnetically pumped free-electron laser with a guide magnetic field, propagation of electromagnetic wave signals through a re-entry plasma sheath in the presence of a strong magnetic field, and magnetic confinement plasmas     

Rotation of polarization and ellipticity of ultrasound in helicon-phonon resonance conditions in indium

Rotation of polarization as well as ellipticity of initially linearly polarized transverse ultrasonic mode have been observed and investigated in helicon-phonon resonance region in single crystal of indium. The peculiarities of the experimental curves of rotation angle and ellipticity have shown, that the considered phenomena are determined by the superposition of three circularly polarized waves: left-handed polarized phonon and two right-handed polarized coupled helicon-phonon modes.     

Angular distribution of low energy photoelectrons with defined spin orientation

On the basis of symmetry arguments general expressions are derived for the angular distribution of photoelectrons in defined spin states from atoms or molecules for the two cases of circularly and linearly polarized light. It is prooved that linearly polarized light or unpolarized light ionizing an isotropic ensemble of atoms or molecules will allways produce unpolarized electrons in all directions in the electric dipole approximation.     

Nonlinear interactions between electromagnetic waves and electron plasma oscillations in quantum plasmas

We consider nonlinear interactions between intense circularly polarized electromagnetic (CPEM) waves and electron plasma oscillations (EPOs) in a dense quantum plasma, taking into account the electron density response in the presence of the relativistic ponderomotive force and mass increase in the CPEM wave fields. The dynamics of the CPEM waves and EPOs is governed by the two coupled nonlinear Schr?dinger equations and Poisson's equation. The nonlinear equations admit the modulational instability of an intense CPEM pump wave against EPOs, leading to the formation and trapping of localized CPEM wave pipes in the electron density hole that is associated with a positive potential distribution in our dense plasma. The relevance of our investigation to the next generation intense laser-solid density plasma interaction experiments is discussed.     

On the development of the method of two-photon absorption for detection of atomic particles

New expressions for the intensity of two-photon absorption by atomic photofragments are derived for the cases of linearly and circularly polarized light and for all possible spin and orbital states of photofragments. It is shown that these expressions can be used in detailed experimental analysis of products of collisions and photochemical reactions since, in particular, they make it possible to determine explicitly the higher order polarization moments of photofragments.     

Scattering of electromagnetic wave by perfect electromagnetic conductor (PEMC) sphere placed in chiral media

A theoretical investigation has been carried out for electromagnetic waves scattering from a perfect electromagnetic conductor (PEMC) sphere which is placed in chiral media. The formulation of the problem is realized by expanding the incident as well as the scattered electromagnetic fields in terms of left circularly polarized (LCP) and right circularly polarized (RCP) waves. By applying the boundary conditions at the chiral-PEMC interface, eight simultaneous equations are generated, which yield the scattering coefficients associated with the Left and Right electromagnetic waves. The relative contribution of Co-polarized and Cross-polarized components of fields to the calculations of scattering cross-section is presented. The effect of admittance parameter and the effect of chirality parameter in cases of lossless, lossy permittivity and lossy permeability on Co and Cross components of scattering cross sections are observed. The results are also compared with available published literatures which are in good agreement.     

两圆偏振光以及线偏振光和圆偏振光干涉图样的衬比度

考察了两束圆偏振光之间以及线偏振光与圆偏振光之间干涉所形成图样的衬比度,并与两束线偏振光之间干涉图样的衬比度进行了比较．指出在非共面多光束干涉中有可能利用圆偏振光以改善干涉图样的整体衬比度,并简要介绍了它在光子晶体制备中的应用．     

Large-amplitude electromagnetic waves in relativistic plasmas

The propagation of linearly polarized large-amplitude electromagnetic waves in relativistic plasmas is studied in the framework of the Akhiezer-Polovin-model. Different forms of the basic equations are reviewed and important solutions are presented for small and critical plasma densities. The well-known periodic solutions are generalized to quasiperiodic solutions taking account of additional electrostatic oscillations.     

Photon and positron generation by ultrahigh intensity laser interaction with electron beams

This study investigates the generation of high energy photons and positrons using focused ultrahigh intensity femtosecond laser pulses on a relativistic electron beam with a set of two-dimensional particle-in-cell simulations. We consider circularly and linearly polarized, single and spatially separated double laser pulses. We model both 500 MeV and 1 GeV electron beams. Higher positron production is obtained using circularly polarized laser pulses. Using double pulses, the focusing effect of the ponderomotive force confines the electrons to a small volume, generating additional energetic photons and positrons. The positron spectral distributions are effectively modified by these variations. When the electron beam energy is doubled, the number of positrons increased, while the cutoff energy remained nearly constant.     

生物组织多光谱偏振特性研究

生物组织内部结构复杂且具有较强的散射特性,而光作为生物组织检测的重要信息载体,其自身特性包括颜色、幅值、偏振等都对信息获取有较大的影响.结合偏振成像,对生物组织多光谱偏振特性展开了研究,依据不同微粒尺寸的分布建立了均匀单层生物组织模型,结合瑞利和米氏散射理论模拟了基于单个微粒的两种散射事件.瑞利散射具有较好的前向后向散...     

Secular free solutions up to third order for two circularly polarized waves in a dissipative plasma medium

The perturbation method of Lindstedt is applied to study the nonlinear effects for two circularly polarized transverse monochromatic waves in a cold dissipative plasma. Amplitude-dependent wavelength and frequency shifts including relativistic corrections are derived.