Broad band resonant light pressure

We solve the previously derived Fokker-Planck equations of laser cooling for several cases: no diffusion processes included, the final stage when the distribution is narrow, and for an ansatz of Gaussian shape at all times. The results are particularized to a transition (j=0)→(j=1) and the numerical values for Mg atoms are used. The results are compared with earlier work on laser cooling and discussed.     

介质不均匀性对激光模式相位与光强分布的影响

将不均匀介质势函数进行泰勒展开,取其前3项近似,与描述光腔模式的亥姆霍兹方程中的特殊函数结合,根据光腔边界条件推导出光腔模式的本征解、激光输出功率以及不均匀介质与激光模式的相位与强度分布关系表达式。将表达式应用于氧碘化学激光器的功率与输出耦合率的非线性拟合以及近场光强分布的分析,预测趋势与文献结果相符。     

哈肯激光方程自脉冲解的稳定性分析

本文详细地研究了哈肯激光方程的自脉冲不稳定性,得出了自脉冲解的解析表达式,并对其进行了稳定性分析。结果表明,无论是对于第三类激光系统还是对于第四类激光系统,哈肯激光方程的自脉冲解都是不稳定的。     

线形腔掺铒光纤激光器输出特性的理论研究

通过求解速率方程，从理论上详细地分析了形腔掺铒光纤激光器输出特性，得到了稳定条件下激光器阈值泵浦功率，输出功率和斜率效率的解析表达式；给出了构造线形腔掺铒光行激光器所需掺铒光纤最短长度和最佳长度的表达式。     

Self-similar solutions of laser produced blast waves

The aerodynamics of the blast wave produced by laser ablation is studied using the piston analogy. The unsteady one-dimensional gasdynamic equations governing the flow are solved under assumption of self-similarity. The solutions are utilized to obtain analytical expressions for the velocity, density, pressure and temperature distributions. The results predict all the experimentally observed features of the laser produced blast waves.     

短密度梯度尺度等离子体中的软X射线激光

通过数值求解等离子体流体力学方程组，研究了短脉冲激光打靶结束后形成的短密度梯度尺度等离子体的冷降温过程，讨论了热传导，膨胀作功，辐射损失三种冷却机制对降温过程的贡献，并用解流体力学方程组得到的等离子参数计算ＭｇＸＩ等离子体中波长小于２０ｎｍ的所有可能跃迁的自发辐射放大增益系数，分析了它们与环境条件的关系，指出了在ＭｇＸＩ等离子体中获取水窗附近乃至水窗波段软Ｘ射线激光的可能性。     

Heating effects induced by a pulsed laser in a semi-infinite target in view of the theory of linear systems

The two-dimensional Laplace integral transform technique is used to solve the problem of heating a semi-infinite target induced by the surface absorption of a laser pulse. Mathematical expressions for the surface temperature and the temperature profile within the target are obtained considering cooling and temperature-dependent absorption coefficient at the front surface. The linear behaviour of the system is found to be established for all cases except for that of temperature dependent surface absorptance. As an illustrative example, computations are carried out on Al, Cu, Ag and Au targets using an empirical formula for the temporal distribution of a measured laser pulse.     

Kinetic modeling of a slow flow CW CO2 laser

A kinetic model for analysis of the slow-flow CW-discharge CO₂ laser with diffusion cooling has been developed in which the gas temperature is obtained from energy balance equations. The method is based on the numerical solution of a set of nonlinear differential equations for vibrational kinetics. The numerical predictions from the model are compared with some experimental results and a good agreement is obtained.     

主被动锁模光纤激光器的脉宽计算及其稳定性分析

分析了主被动锁模光纤环形孤子激光器的运行机理，用分裂步长法进行了数值模拟，获得了重复频率为１０ＧＨｚ，脉宽为９８５ｆｓ的稳定的孤子脉冲序列，通过孤子参量演化方程的求解，获得了光结环形孤子激光器的稳定运行条件及孤子脉宽的解析表达式。     

Optimization of GaAs semiconductor saturable absorber Q-switched lasers

The expressions of pulse characteristics such as output energy, peak power, and pulse width are obtained by solving the coupled rate equations describing the operation of GaAs semiconductor saturable absorber Q-switched lasers. The key parameters of an optimally coupled GaAs saturable absorber Q-switched laser are determined and several design curves are generated from these expressions for the first time. These key parameters include the optimal normalized coupling parameters and the optimal normalized saturable absorber parameters that maximize the output energy or maximize the peak power, and the corresponding normalized energy, normalized peak power, and normalized pulse width. Using the expressions and design curves, one can predict the pulse characteristics and perform the design of an optimally coupled GaAs saturable absorber Q-switched laser.     

Free-electron laser with the slow wave medium

One-dimension linear theory for free-electron laser with the slow wave medium is set up in terms of Fourier transform in the paper. The eigen fields for the free-electron laser are found and the derivation of the dispersion equations for interaction of electrons with the fields is made. The approximate and analytic expressions for the growth are given. Based on the eigen fields obtained, the mechanisms for the co-gyrotron synchronization and for the inverse-gyrotron synchronization are expounded.     

光滑激光脉冲作用下的强场自电离

本文研究了光滑激光脉冲作用下包含高阶离化的强场自电离过程,导出了其中的基本方程,得到了基态布居和光电子谱的一系列解析表达式。讨论了指数增长脉冲作用时的具体结果,发现高能谱比低能谱更能呈现出光电子谱在脉冲光作用下特有的多峰分裂。     

Optimization of the Readout Fidelity of the Quantum State of an Optical Qubit in the 171Yb+ Ion

JETP Letters - A scheme based on a laser cooling system has been proposed to detect the state of an optical qubit in the 171Yb+ ion. Analytical expressions have been derived for the...     

Laser cooling of quasi-free atoms in a nondissipative optical lattice

A quasi-classical theory of laser cooling is applied to the analysis of cooling of unbound atoms with the angular momenta 1/2 in the ground and excited states in a one-dimensional nondissipative optical lattice. In the low-saturation limit with respect to the pumping field, the mechanisms of cooling can be interpreted within the framework of an effective two-level system of ground-state sublevels. In the limit of weak Raman transitions, the mechanism of cooling of unbound atoms is similar to the Doppler mechanism known in the theory of a two-level atom; in the limit of strong transitions, the mechanism of cooling is analogous to the well-known Sisyphys mechanism. In the slow-atom approximation, analytical expressions are obtained for the friction (drag) coefficient and the induced and spontaneous diffusion, and the kinetic temperature is estimated.     

Fields of a radially polarized Gaussian laser beam beyond the paraxial approximation

Analytic expressions for the fields of a tightly focused radially polarized Gaussian laser beam are derived, accurate to epsilon5, where epsilon is the associated diffraction angle. The fields satisfy Maxwell's equations, and the calculated beam power based on them is significantly different from that of the paraxial-approximation fields.     

The wavelength sensitivity of back-scattering

The effect of wavelength variations on the backscattering of laser light from contoured or shaped objects is analyzed. In order to consider remote sensing by frequency-scan means, equations are derived for the transforms of the signal field and its intensity and for the correlation functions appropriate in the study of rough objects. In these expressions, interesting dependences upon object shape, roughness, and orientation are found. In experiments using roughened plates and spheres illuminated by a tunable dye laser, good agreement with theory is observed.     

激光场对快速分子离子与固体相互作用的影响

利用线性化的流体力学方程和泊松方程，描述了在强激光场作用下快速分子离子在固体中产生的电激发过程，并推导出分子离子中两个离子之间的动力学相互作用势和相互作用力的一般表达式.通过数值求解离子的运动方程，研究了激光场的参量对分子离子库仑爆炸过程和能量损失的影响. 关键词： 激光场 分子离子 库仑爆炸 能量损失     

Rate-equation approach to laser light statistics

Single-mode cavity laser light statistics is considered within the framework of rate equations. According to this approach, fluctuations are caused by jumps in active and detecting atoms. The algebra is simple, allowing analytical expressions for the intracavity Fano factor and the photocurrent spectral density to be obtained. Poissonian, quiet, and optical pumps are considered. The results are verified by comparison with Monte Carlo simulations. An essentially exhaustive investigation of sub-Poissonian light generation by classical laser schemes, two-mode lasers, and semiconductor lasers is proposed.     

无内热激光器运转对抽运光光强的需求条件研究

研究了无内热激光器和激光放大器运转时对抽运光的需求条件.运用激光器的速率方程理论,给出了抽运光所应满足条件的表达式.无内热激光运转时,不仅要求抽运光光强要大于阈值条件,而且要大于某个最小抽运光强(与增益材料性质、抽运光波长、激光波长等有关).以掺镱的KY(WO4)2晶体为无内热激光器的放大介质,计算了抽运光光强应满足的空间分布条件.要使激光器无内热运转,抽运光光强需随激光光强的增大而相应减小.对于无内热激光器,抽运光光强的空间分布与谐振腔前后镜的反射率和增益介质长度密切相关,在谐振腔输出耦合镜反射率不是太低的情况下,腔内抽运光强需近似为均匀分布.