作　　者： ; ; ; ;

机构地区： 五邑大学信息工程学院

出　　处： 《五邑大学学报（自然科学版）》 2011年第3期1-6,共6页

摘　　要： 利用有效粒子法,研究了折射率有纵向和横向调制的强非局域非线性介质中椭圆高斯光束的传输特性,得到了光束中心在不同调制情况下的演化规律.解析和数值结果表明:无纵向调制时,介质二相等(不相等)的横向调制频率(k x,k y)将使初始偏离二坐标轴较小的光束中心演化具有相同(不相同)的振荡周期;当光束中心初始偏离某一坐标轴较远,若k x≠ky,光束中心将分别独立地做等幅周期振荡,但若k x=ky,光束中心周期振荡,且其振荡幅度将沿初始偏离坐标轴较小的方向逐渐指数增长而沿初始偏离坐标轴较大的方向指数衰减;当介质有纵向调制时,若纵向调制频率k z和k x、k y之间满足特定条件,则光束中心沿该横向振荡的幅度随传输距离的增加而指数增长,之后又指数减小;若不满足该频率条件,则光束中心将按不同的频率等幅周期振荡. The evolution of elliptically Gaussian beam in the strongly nonlocal nonlinear media with longitudinal and transverse periodic modulations of the linear refractive index is studied by employing the effeetive-partical approach. The propagation properties for the beam center are obtained in the different modulations. The analytical and numerical results are shown in the ease of no longitudinal modulation： The same （different） frequency of transverse modulation will lead to the same （different） oscillating period for the beam center when the initial beam center displacement along the transverse axes is small; but when the initial beam center displacement along a certain transverse axes is very large, the beam center will oscillate periodically with the amplitude unchanged; if the transverse modulation frequencies are not equal, the beam center will oscillate periodically; and the amplitude of the small （large） initial beam center displacement along the transverse axes decreases（grows）exponentially if transverse modulation frequency is the same. In the case of the longitudinal periodic modulation, if the relation of the longitudinal modulation frequency and some transverse refractive-index modulation frequency condition is satisfied, the oscillation amplitude of the beam center will grow exponentially along this very transverse direction with the propagation distance, and decrease later. But if the frequency condition is not satisfied, the beam center will oscillate periodically with amplitude unchanged.

关 键 词： 非线性光学 非局域非线性薛定谔方程 有效粒子法 空间光孤子

领　　域： [机械工程] [理学] [理学]