强光场下类氢原子的电离能谱

用Ｆｌｏｑｕｅｔ方法迭代求解强光场下类氢原子的Ｓｃｈｒｏｅｄｉｎｇｅｒ方程,较严格地计算线极化光场下的波函数,并用电离边界条件,求出复本征值,最后得到多光子共振电离公式,并与实验比较。     

用缀饰原子法研究强激光场驱动下的共振荧光

本文用缀饰原子方法研究了单模激光场驱动下的两能级原子系统的共振荧光.通过在主方程中唯象地引入激光模的激发项补偿散射过程,使该模式中光子数减少.得到了主方程的定态解.并由此得到了共振荧光谱的强度分布及谱线形状.     

强光场中类氢原子的理论描述

提出了描写强光场中类氢原子状态的新理论方法.同时给出强光场中类氢原子波函数的近似解析表达式.利用这个表达式通过数值计算得到的类氢原子电离谱与实验谱符合得很好.同时将这个新理论方法用于讨论高阶谐振产生也得到了满意的结果 关键词：     

数值求解三维含时Schr?dinger方程及其应用

发展了一套高精度、高效率的伪谱方法,以非微扰的方式求解真实原子三维含时Schrdinger方程.该方法选用二阶劈裂算符作为时间演化算子,分别选择能谱表象和坐标表象作为含时波函数演化的两个表象.在坐标表象下波函数的径向部分使用库仑波函数离散变量表象来离散;角向波函数展开在两维的Gauss-Legendre-Fourier格点上.以H原子的光激发和光电离过程为例,进行了数值计算并和解析解进行了比对.结果表明二者符合很好.该方法很好地处理了库仑奇点问题.还计算了强激光辐照H原子的多光子电离过程,并和其他的数值方案进行了比较.结果表明,在计算收敛的前提下本方法计算效率更高. 关键词： 三维含时Schrdinger方程 库仑奇点 强场 含时波包传播     

关于氢等离子体光谱谱线迭合问题

本文首先求解了电子在级数型势场中的定态薛定谔方程条件是r→∞时V(r)→0;t≤2。得到决定电子定态能级和波函数的几个公式。作为这些公式的应用,文中以完全电离等离子体为例,利用德拜势讨论了氢等离子体光谱谱线的加宽和谱线的迭合问题。     

自旋为2的Bargmann-Wigner方程的严格解

在坐标表象中严格求解自旋为2的Bargmann-Wigner方程,导出了自旋为2的场（m≠0）的相对论性场方程和动量表象波函数。     

强光场中电子系统与多光子的相互作用

在非相对论量子场论框架下,给出电子场和光子场相互作用时整个系统的哈密顿量H_tot,研究在强光场中非线性项即A²项的作用.电子系统用Fermi-Dirac统计的Schr?dinger量子波场描述.采用“自洽平均场”和“有效质量”近似,并基于位移谐振子的相干态方法,得到电子波光量子场算子函数的Lee-Low-Pines表式f(b⁺),再利用算子函数f(b⁺)对算子b+的微商公式,导出了相关理论计算公式,其中包括电子能量E< 关键词： 强光场 多光子 非线性光学     

含克尔介质高Q腔内"单模场单原子”系统的腔场谱

研究了充满克尔介质的高Q腔和二能级原子系统的腔场谱,讨论了克尔效应对谱结构的影响,发现克尔介质与腔场的耦合会使数态光场腔场谱中的原共振谱线分裂成频差为2χ的双线,且双线的“中心频率”随初态光子数的增加而远离共振频率。当初始光场为光子数态的叠加态时,腔场谱在强耦合情况下一般为多峰结构,峰的个数随着初始平均光强的增大而增加。     

两双能级原子与双模腔场多光子共振相互作用辐射谱的一般特征

本文从非相对论量子电动力学理论的普遍原理出发,首先建立了与J-C模型相关的“双模腔场-两原子”系统的多光子相互作用模型,并求得本征算符在共扼相互作用情形下的本征函数展开式;然后,重点研究了两个通过偶极-偶极力关联的有效二能极原子与双模腔场多光子共振相互作用辐射谱的一般特征。结果表明,当双模腔场分别处于不同数态时,辐射谱一般呈现出非对称的8峰结构,但在不同的条件下,辐射谱会呈现出数目不等、形状各异的谱线。两原子非简并双光子J-C模型的辐射谱可作为特例得出。     

自旋为5/2的Bargmann-Wigner方程的严格解

在坐标表象中严格求解自旋为5/2的Bargmann-Wigner方程,导出了自旋为5/2的场(m≠0)的相对论性方程和动量表象波函数 关键词： 自旋为5/2的场(m≠0) Bargmann-Wigner方程 坐标表象 严格解     

电子在激光驻波场中运动产生的太赫兹及X射线辐射研究

采用单电子模型和经典辐射理论分别对低能和高能电子在线偏振激光驻波场中的运动和辐射过程进行了研究. 结果表明: 垂直于激光电场方向入射的低速电子在激光驻波场中随着光强的增大, 逐渐从一维近周期运动演变为二维折叠运动, 并产生强的微米量级波长的太赫兹辐射; 高能电子垂直或者平行于激光电场方向入射到激光驻波场中, 都会产生波长在几个纳米的高频辐射; 低能电子与激光驻波场作用中, 激光强度影响着电子的运动形式、辐射频率以及辐射强度; 高能电子入射时, 激光强度影响了电子高频辐射的强度, 电子初始能量影响着辐射的频率; 电子能量越高, 产生的辐射频率越大. 研究表明可以由激光加速电子的方式得到不同能量的电子束, 并利用电子束在激光驻波场的辐射使之成为太赫兹和X射线波段的小型辐射源. 研究结果可以为实验研究和利用激光驻波场中的电子辐射提供依据.     

Relativistic nonperturbative above-threshold phenomena in strong laser fields

Relativistic features of various nonperturbative above-threshold phenomena in strong laser fields are discussed and compared. This includes above-threshold ionization of multiply charged ions as well as pair production in an ultrastrong laser wave, superimposed with either a nuclear Coulomb field or another counterpropagating laser wave. For the probability of above-threshold pair production, a new scaling relation is given. Particular attention is paid to similarities among these processes, regarding the energy and angular spectra of the particles as well as the total reaction rates.     

激光场中类氢原子的电离本征值

光场下类氢原子的Schrdinger方程可用缀饰势方法求解.波动方程展开为Floquet分波后,可以得到弱光场或强光场下近似的径向波函数和复的电离本征值,然后计算了共振能量和半宽度.     

Hydrodynamics of Plasma Interaction with an Intense Laser Field

A set of moment relations, which can describe the charged fluids response to an intense pump laser, and a linearization substitution relation, which is more appropriate as compared with the past treatment, are given by theoretical analyses. The relevant equations of state (adiabatic and isothermal), momentum and energy equations are derived self-consistently.The dispersion relations of the electron plasma wave and the ion acoustic wave driven by an intense pump laser field are-obtained. The results show that the frequencies of both the excited electron plasma wave and the excited ion acoustic wave have a great modification in the case of strong pump. The former bears out the theoretical result obtained from Vlasov equation and the later is consistent with experimental observations. It is proved that the zero-frequency component of the laser light wave contribution to the plasma pressure tensor is un-neglected,which implies a greatly change to the wave excitation properties, particularly in the direction of parallel or approximately parallel to the laser field vector.     

弱光场下电子与库仑势散射的微扰解

外光场下电子与库仑势散射的Schr?dinger方程可用Floquet分波法分离变量,径向波动方程是一组无限耦合的二次线性微分方程组,当弱外光场可视为微扰,方程组将近似为二次常微分方程并且可积,由此可得径向波函数、S矩阵、截面。无论何种极化或是否作偶极近似,共振谱线是普遍存在的,并给出共振能量和强度的计算公式。     

Attosecond electron wave packet dynamics in strong laser fields

We use a train of sub-200 attosecond extreme ultraviolet (XUV) pulses with energies just above the ionization threshold in argon to create a train of temporally localized electron wave packets. We study the energy transfer from a strong infrared (IR) laser field to the ionized electrons as a function of the delay between the XUV and IR fields. When the wave packets are born at the zero crossings of the IR field, a significant amount of energy (approximately 20 eV) is transferred from the field to the electrons. This results in dramatically enhanced above-threshold ionization in conditions where the IR field alone does not induce any significant ionization. Because both the energy and duration of the wave packets can be varied independently of the IR laser, they are valuable tools for studying and controlling strong-field processes.     

Quantum processes in short and intensive electromagnetic fields

This work provides an overview of our recent results in studying two most important and widely discussed quantum processes: electron-positron pairs production off a probe photon propagating through a polarized short-pulsed electromagnetic (e.g. laser) wave field or generalized Breit–Wheeler process, and a single a photon emission off an electron interacting with the laser pules, so-called non-linear Compton scattering. We show that the probabilities of particle production in both processes are determined by interplay of two dynamical effects, where the first one is related to the shape and duration of the pulse and the second one is non-linear dynamics of the interaction of charged fermions with a strong electromagnetic field. We elaborate suitable expressions for the production probabilities and cross sections, convenient for studying evolution of the plasma in presence of strong electromagnetic fields.     

强激光等离子体中的自由电子波函数

借助激光等离子体的光学度规,严格求解了弯曲时空中的狄喇克方程,得到了强激光等离子体中的自由电子波函数。当激光场为零时,该波函数自然地过渡到相对论的自由电子波函数。简单地讨论了该波函数可能的应用。 关键词：     

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     

Observation of collimation and decollimation of an atomic beam in a misaligned standing wave

This paper reports an experimental study on the collimation and decollimation of an atomic beam in a misaligned standing wave, in which the effective detuning caused by the Doppler effect is affected by the longitudinal velocity of the atomic beam. The experiment shows that in a strong field with red detuning between laser field and atomic transition frequency, laser heating in a normal standing wave becomes laser cooling in a misaligned standing wave for an approriate misalignment angle. For blue detuning, laser cooling in a standing wave can also become laser heating in a misaligned standing wave for an appropriate condition. These results ca be used in controling atomic motion.