基于BiB3O6晶体的飞秒光参量变换特性

对基于新型非线性晶体BiB₃O₆(BIBO)的飞秒光参量变换过程的参量特性进行了研究. 计算了BIBO晶体三个光学主平面内的相位匹配条件和有效非线性系数,确定了克尔透镜锁模钛宝石激光器的基频光与倍频光抽运时最佳的光学主平面和相位匹配方式,并分析了三波的时间走离和空间走离,以及信号光的参量增益和带宽. 为利用基于BIBO晶体的飞秒光参量技术获得高能量、宽调谐、窄脉宽的光源提供理论依据和实验指导. 关键词： 3O₆')" href="#">BiB₃O₆ 光参量变换 共线相位匹配 光学主平面     

利用光孤子机制实现超宽范围波长调谐的理论和实验研究

以获得光参量啁啾脉冲放大系统主激光与抽运光两种波长、宽带、超短脉冲的产生及精密同步为目标,探索采用光孤子机制实现超宽带宽范围的可调谐超短脉冲产生. 数值模拟了孤子传输过程中的时域-频域演化过程及与其他非线性效应的相互作用过程和特性. 实验验证了利用光孤子机制产生可调谐脉冲的方法. 同时还观察到孤子的形成、分裂、自频移等现象,在可见光到近红外波段都演示了波长可调谐的输出特性,并且与理论分析结果符合较好. 关键词： 光参量啁啾脉冲放大 可调谐脉冲产生 非线性薛定谔方程 孤子机制     

光参量荧光寿命分布

 根据荧光寿命定义和放大过程获得的增益方程,研究了新型非线性晶体BaAlBO₃F₂中三种不同的相位匹配模式下中心波长532 nm泵浦的参量荧光光子寿命的分布特性。结果表明,当注入单色信号光时,参量荧光寿命随泵浦光相位匹配角的增加由椭圆体分布变化为圆环体分布。采用宽带信号光时,则由分散分布改变为集中在近200 nm波长范围内分布,并随泵浦光相位匹配角的增加而逐步减小。考虑宽带泵浦光注入情况时,参量荧光寿命的分布范围由于相位匹配范围增加而随之扩展。     

具有非倍测度的参数型Marcinkiewicz积分交换子在Hardy空间的有界性

主要证明了由参数型Marcinkiewicz积分M~p和Lipschitz函数b生成的交换子M_b~p的有界性.在M的核满足一定的条件下,证明了M_b~p不仅从Lebesgue空间L~(n/(n-β))(μ)到Hardy空间H~1(μ)有界,而且从Lebesgue空间L~(n/β)(μ)到RBMO(μ)有界.     

GENERAL MINIMAX ESTIMATORS ON THE LOCATION MATRIX OF A MIXTURE OF NORMALS

This paper considers the estimate problem on the mean matrix of mixtureof normals. In order to evaluate estimators of the mean matrix, a fundamental frameof Ф-(general) decision problem is established. Under the frame, a class of Ф-minimax estimators are constructed.     

Chaotic motions in the resonant separatrix band of a parametrically excited pendulum

The energy increment spectrum method is developed for the numerical prediction of the appearance and disappearance of a primary (2M: 1)-librational or (M: 1)-rotational resonant separatrix band in a parametrically excited pendulum. The analytical conditions for the presence of such separatrix bands are also obtained. Illustrations of the analytical and numerical results for the appearance and destruction of the resonant bands are given for a comparison.     

Global Parametric Sufficient Efficiency Conditions for Semiinfinite Multiobjective Fractional Programming Problems Containing Generalized （a,n,p）-V-Invex Functions

In this paper, we discuss numerous sets of global parametric sufficient efficiency conditions under various generalized (α, η, ρ)-V-invexity assumptions for a semiinfinite multiobjective fractional programming problem.     

Nonlinear Normal Modes of a Parametrically Excited Cantilever Beam

We investigate theoretically thenonlinear normal modes of a vertical cantilever beam excited by aprincipal parametric resonance. We apply directly the method ofmultiple scales to the governing nonlinear nonautonomousintegral-partial-differential equation and associated boundary conditions.In the absence of damping, it is shown that the system has nonlinear normal modes, as defined by Rosenberg, even in the presence of the parametric excitation.We calculate the spatial correction to the linear mode shapedue to the effects of the inertia and curvature nonlinearities andthe parametric excitation. We compare the result obtained withthe direct approach with that obtained using a single-mode Galerkindiscretization.The deviation between the two predictions increases as the oscillationamplitude increases.     

A parametric view on the Mangasarian–Fromovitz constraint qualification

The growth of the multipliers, when the parameter approaches such a critical parameter, is characterized by a parametric constraint qualification which is introduced here. It is equivalent to a bound on the growth of the multipliers. Received May 8, 1995 / Revised version received February 12, 1998 Published online February 25, 1999     

Bifurcations in parametric nonlinear programming

Bifurcation and continuation techniques are introduced as a class of methods for investigating the parametric nonlinear programming problem. Motivated by the Fritz John first-order necessary conditions, the parametric programming problem is first reformulated as a closed system of nonlinear equations which contains all Karush-Kuhn-Tucker and Fritz John points, both feasible and infeasible solutions, and relative minima, maxima, and saddle points. Since changes in the structure of the solution set and critical point type can occur only at singularities, necessary and sufficient conditions for the existence of a singularity are developed in terms of the loss of a complementarity condition, the linear dependence constraint qualification, and the singularity of the Hessian of the Lagrangian on a tangent space. After a brief introduction to elementary bifurcation theory, some simple singularities in this parametric problem are analyzed for both branching and persistence of local minima. Finally, a brief introduction to numerical continuation and bifurcation procedures is given to indicate how these facts can be used in a numerical investigation of the problem.This research was supported by the Air force Office of Scientific Research through grant number AFOSR-88-0059.