开放的V型无反转激光系统中光场的横向效应

利用开放的V型系统密度矩阵运动方程组和Hurwitz判据研究了光场的横向效应。结果表明：与平面波近似情况相比，光场的横向分布将使系统通过无激光解失稳而导致无反转激光(LWI)的方式发生明显的改变，并使系统更容易通过pitchfork分岔失稳而获得LWI；激活介质横向尺寸与光束束腰的比值对能够产生LWI的失稳区的大小具有决定性的影响，而且Raman反转区随这个比值增大而增大；非饱和增益、腔损耗、原子注入速率比以及退出速率的变化对于能够产生LWI的失稳区的影响与平面波情况是大不相同的。     

Ne—H2激光输出光场的观察

本文报导了横向快放电激发下Ｎｅ２－Ｈ２激光输出光场随各参量的变化关系，给出了激光输出特性，讨论了泵浦机制。     

玻色-爱因斯坦凝聚原子与Schr(o)dinger猫态相互作用系统中的压缩特性

利用全量子理论,研究了玻色-爱因斯坦凝聚原子与Schrodinger猫态相互作用系统中,光场和原子激光的压缩特性.结果表明;在系统中,偶相干态、奇相态分别与玻色-爱因斯坦凝聚原子相互作用,偶相干态、奇相态光场和原子激光均不呈现压缩效应.而Yurke-Stoler相干态光场和原子激光呈现压缩效应.在强场(|α|=1)情况下,三种不同光场的两种压缩现象均不产生.光场和原子激光的压缩特性主要受初始光强和耦合常数的影响.     

玻色-爱因斯坦凝聚原子与Schr?dinger猫态相互作用系统中的压缩特性

利用全量子理论,研究了玻色-爱因斯坦凝聚原子与Schr?dinger猫态相互作用系统中, 光场和原子激光的压缩特性。 结果表明: 在系统中,偶相干态、奇相态分别与玻色-爱因斯坦凝聚原子相互作用,偶相干态、奇相态光场和原子激光均不呈现压缩效应。 而Yurke-Stoler相干态光场和原子激光呈现压缩效应。 在强场 (|a|=1)情况下,三种不同光场的两种压缩现象均不产生。 光场和原子激光的压缩特性主要受初始光强和耦合常数的影响。     

基于激光末端引导的无人机精确回收技术

为了提高野外复杂环境下无人机回收的回收精度及回收成功率,采用了基于激光末端引导体制的无人机精确回收方法,对激光末端引导精确回收无人机系统的工作原理及流程进行了理论分析和验证,取得了无人机引导距离段与激光引导光场辐射场以及无人机偏航角度信息与系统精确回收之间的数据关系。结果表明,在距离着落点1km~2km的粗引导距离段,保持恒定40m的激光引导光场辐射场,可以使无人机快速进入激光辐射场调整偏航角度信息,提高回收的可靠性;在中间距离段,激光辐射场与着落距离按线性关系变化,有利于粗引导转入精确引导阶段;在距离着落点500m以内的精确引导距离段,保持20m的激光引导光场辐射场,可以提高无人机系统的回收精度。将该方案应用到无人机的回收系统中,可以显著提高无人机在复杂环境下的回收精度。     

基于激光冷却技术的中性锶原子特性研究

为了研究碱土金属类的中性锶原子在多普勒冷却激光场中的冷却特性,从Heisenberg方程出发,采用激光冷却理论分析得到锶原子在能级跃迁（5s2）1S₀~（5s5p）1P₁ 1维驻波激光光场和3维磁光阱中冷却效果与激光强度、失谐量等冷却激光场参量的关系。结果表明,当锶原子处在1维驻波激光光场中且在弱激光光场、频率小失谐条件下,锶原子所受耗散力与这两个参量呈线性关系,但当两个参量增长至一定程度时耗散力呈现饱和现象;当锶原子在3维磁光阱中且当阱中激光光场的频率失谐为-16MHz时,碱土金属锶原子有最低冷却温度,约为0.76mK。对多普勒冷却光场中性锶原子特性的分析为其它碱土金属类原子的冷却研究提供了一定的理论指导。     

Ne－H_2激光输出光场的观察

本文报导了横向快放电激发下Ｎｅ－Ｈ_２激光（λ＝５８５．３ｎｍ）输出光场随各参量的变化关系，给出了激光输出特性，讨论了泵浦机制．     

利用V型三能级原子玻色-爱因斯坦凝聚体与双模压缩光场相互作用制备双模原子激光

研究了Ⅴ型三能级原子的玻色-爱因斯坦凝聚体(BEC)与双模压缩相干态光场相互作用系统的量子动力学行为，分析了利用Ⅴ型三能级原子BEC与双模压缩相干态光场相互作用制备双模原子激光的可能性。结果表明：在光场作用下，Ⅴ型三能级原子BEC中被激发到非俘获态的原子，仍保持其相干态的特性，从而在理论上证明了利用Ⅴ型三能级原子BEC与双模压缩相干态光场相互作用可以产生双模原子激光。     

激光诱导分子的局域模振动

提出了两激光场与三能级分子相互作用系统中，调制光场的振幅和位相，诱导分子的局域模振动，并讨论了分子的动力学规律。     

基于光场分布特性分析的高功率激光吸收体设计方法研究

高功率激光装置需要利用激光吸收体实现对杂散光的有效管控。然而吸收体受光面交界处极易发生激光损伤，可能导致激光装置内部的洁净环境受到污染。为了解决这一问题，基于有限元分析方法，模拟了高功率激光吸收体受光面交界处在包括无过渡、圆弧过渡和平面过渡等不同过渡条件下介质内部的光场分布，分析了吸收玻璃界面对光场的影响，得到了介质内部光场峰值强度及峰值位置的变化规律。结果显示:吸收体的损伤可能是由于过渡面为曲面导致的。研究工作为吸收玻璃的激光损伤研究和吸收体设计提供参考。     

单模激光场与N个原子相互作用理论

本文用玻色算符的三维型哈密顿量描述单模激光场与Ｎ个两能级原子的相互作用。在原子系统处于低能态、光子数很大的初始条件下得到了作用系统的动力学变化规律。     

Modified Fabry–Perot and Rate Equation Methods for the Nonlinear Dynamics of an Optically Injected Semiconductor Laser

Modifications have been introduced to the Fabry– Perot (FP) and the rate equation methods to improve the accuracy of the analysis of the nonlinear dynamics of a laser with external optical injection. Comparison between the modified methods and the more accurate transmission-line laser model (TLLM) shows good agreement, while the computational time of the latter is larger by two or three orders of magnitude. In the FP method, the stimulated recombination term in the carrier density evolution equation is modified to include the backward propagating wave and the exponential longitudinal dependence of the electromagnetic field. In the rate equation method, the optical injection term is modified to account for the contribution of the amplification and losses of the injected light inside the cavity to the average photon density. The derivation explaining the validity of these changes and the mathematical relationship between the two methods is presented. Improved stability maps for different values of the injected optical power and frequency detuning are demonstrated and compared with those obtained by the TLLM. The gain compression effect is included in the FP model, and its effect on the stability properties is discussed.      

端面抽运DPAL三维模型及激光输出特性的模拟研究

根据激光三能级速率方程理论,考虑抽运光聚焦的空间分布,建立三维DPAL速率方程组的理论模型,结合激光系统运行的边界条件,通过数值方法,对模型进行求解,对端面抽运铷蒸气激光器的输出特性进行了详细分析,包括抽运光聚焦光斑半径、聚焦位置、蒸气池长度等参量对模式匹配效率、阈值抽运功率和斜率效率的影响。在模式匹配最佳时,计算了对介质长度对激光输出和阈值的影响。根据抽运光功率,以获得最大激光输出功率为目标,给出了激光器系统的优化参数,包括介质长度、抽运光聚焦在介质中的聚焦位置、输出耦合反射率。     

Heterodyne detection with an injection laser I. principle ofoperation and conversion efficiency

If a light signal is passed into the resonant cavity of an actively oscillating injection laser, an electrical signal at the difference between the laser and light signal frequencies flows through the wire supplying the DC bias to the laser. A small-signal analysis of heterodyne detection with such a laser oscillator that is based solely on rate equations and introduces the externally applied signal as a source term into the photon rate equation is discussed. Since neither Maxwell's equations nor the wave equation are involved, this analysis is deemed simpler and more transparent than that reported earlier. Gain saturation of the active medium of the laser, which is responsible for broadening of the relaxation resonance, is taken into account     

Period tripling and chaos in the dynamic behavior of directlymodulated diode lasers

The paper presents the relevance of period-tripling behavior that has recently been found in different experimental studies of directly modulated laser diodes. Applying different numerical techniques to the rate equation model of the laser diode, among which we highlight the continuation method to calculate the unstable solutions of the system, we show that period-tripling behavior appears and disappears in two tangent bifurcations. Therefore, the period-three solutions form a closed bifurcation curve called isola. In between these two tangent bifurcations, the period-three solution coexists with the chaotic attractor reached by a period-doubling cascade, giving rise to a hysteresis loop in the deterministic case. Also, we have found that a boundary crisis might be behind the chaotic behavior that is observed for the highest values of the modulation index. The effects of random noise fluctuations in the laser diode dynamics are also studied. Langevin noise sources are included in the rate equation model and appropriate stochastic integration methods have been used. The route to chaos that we have obtained points out the relevant role that noise has in achieving agreement between numerical studies and experimental results that have been published. The introduction of noise has been proved to be of major importance in determining the system behavior in the regions of the coexistence of solutions     

双光子激光的时间行为

对于双光子激光器的Maxwell-Bloch方程进行了多重时间尺度微扰分析,给出了该系统随不同时间尺度演化的动力学行为。     

Single-particle theory of the free-electron laser in a moving frame

We give a summary of the theory of a single electron involved in free-electron laser (FEL) operation. We use the method of transformation to a predetermined moving frame where the wiggler-laser scattering process is elastic. In this paper, we discuss the classical and quantum dynamics of such an electron and evaluate perturbatively the lowest order FEL behavior from the classical pendulum equation. The presentation is tutorial throughout and stresses analytic results and physically significant dimensionless parameters. No results are included for the dynamic evolution of the light during the laser action.     

水下激光告警器信噪比分析计算及仿真

在反猎雷预警系统中,激光告警设备主要用来识别敌对激光信号的方位。水体对激光衰减使告警器性能降低,对光的吸收使接收器信噪比降低,散射使定向精度变低。使用传输方程理论建立了激光在水下传输模型,运用傅里叶变换及平面波扩展方法求解水体传输方程。利用光的互易原理及传输方程得到了探测器平面上的二维空间光强分布模型。仿真计算了探测器在清洁海水、近岸海水、浑浊海水等海水环境时直射光与散射光的响应。仿真实验结果表明所提出的方法可用于评估水下告警系统探测器接收性能。     

Numerical Study of Doppler Dynamics in Self-Mixing Semiconductor Lasers

We present a new approach for performing numerical simulations of optical feedback semiconductor lasers for moving targets. The derived rate equation for the complex electric field is suitable for the numerical analysis of the dynamics in a self-mixing semiconductor laser with a Doppler frequency shift. We present numerical examples calculated using the rate equations.      

Rate equation models and wavelength modulation in semiconductor diode lasers

Various aspects of the rate equation model of a diode laser are discussed in light of the dielectric waveguide model of the laser. Precise definitions of various quantities used in the rate equation model are given. Emphasis is on analysis of wavelength modulation or chirp. It is shown that the so-called linewidth enhancement factor relevant for predicting wavelength modulation must be defined in a way that depends on laser structure and modulation frequency. A number of proposed mechanisms leading to wavelength modulation are compared directly within the framework of the waveguide model.