A theoretical investigation is carried out into the cross phase modulation (XPM) in an asymmetric double AlGaAs/GaAs quantum wells structure with a common continuum. It is found that, combining resonant tunneling-induced transparency and constructive interference in the third-order Kerr effect, a giant XPM can be achieved with vanishing linear and nonlinear absorptions, accompanied by the velocities of the probe and signal fields being matched. Furthermore, this giant XPM could induce a \pi-phase shift at a single-photon level which is favorable for the applications in two-qubit quantum logic gates.

We propose two schemes of atom localization based on the interference of double-dark resonances in a tripod and a 'Lambda'-type four-level system. It is demonstrated that the localization is significantly improved owing to the interference of double-dark resonances. In the tripod scheme, the localization can be manipulated by the parameters of an additional control field. Via adjusting the Rabi frequency of the field, one can double the probability of detecting the atom within subwavelength domain. By decreasing the detuning of the field, higher spatial resolution can be achieved. In the 'Lambda'-type four-level system, via adjusting the probe field detuning, we can not only make the atom localized at the nodes of the standing-wave field with high precision, but also increase the detecting probability of the atom at a particular position by a factor of 2.

We propose two dense gas schemes of four-level 'Lambda'-type and V-type atoms based on the effect of quantum coherence. It is shown that under certain conditions the dense gas can simultaneously exhibit negative permittivity and negative permeability, and thus become a negative refractive-index material. Furthermore, by analyzing the absorption property of the left-handed materials, we find that the absoption can be reduced via choosing appropriate parameters. Such schemes might be used to fabricate isotropic and homogeneous left-handed material with vanishing absorption in a wider optical frequency band.

对于在ω-2ω双色场作用下的原子,在两种不同电离机制下探讨了电离过程的相位效应.结果发现在隧穿机制下总电离率随相对相位的变化呈“∩”形,而在过势垒机制下呈“∪”形.研究说明利用双色场对原子电离过程进行相位控制是可行的.

理论研究了BBO晶体在Ⅰ型相位匹配下非共线情况时的激光参量放大特性.研究结果表明,对于一定波长的抽运光,存在一定的非共线入射角对应一定波长的信号光,使在较高的激光增益下增益带宽最大,同时温度的调谐也对增益谱的形状有部分影响.这对于短激光脉冲的激光参量放大的优化具有重要意义.

介绍了新近提出的光学啁啾脉冲参量放大技术,并以高增益、宽谱带的双轴非线性晶体LBO为例,研究了抽运光和信号光的相位匹配角的关系、增益、增益带宽、匹配角的选择,以及增益随晶体长度变化的趋势和双曲正割和高斯脉冲输入非线性晶体前后变化的情况。

报道了在光参量啁啾脉冲放大全新原理验证方面取得的最新实验研究结果。

用数值求解一维含时薛定谔方程的方法计算了由频率分别为ω及1.5ω的激光组成的双色场作用下的模型原子产生的高次谐波谱。 发现由于双色场的相干效应, 在其谐波谱中不仅产生了奇次谐波, 还产生了偶次谐波和半整数次谐波。 分析了各次谐波产生的原因以及对谐波转化效率产生影响的主要因素。

利用强激光场驱动下的原子二能级模型,探讨了高次谐波与高阶拉曼谱的相干相消现象。结果发现适当选取激光场的强度使高阶拉曼线处于谐波位置时,由于相干效应,高阶拉曼谱得到抑制而高次谐波谱则得到加强。

电子关联效应在负离子中的作用相当重要,本文讨论了负碳离子(2s22p3)和(2s12p4)的能级结构、光谱跃迁、寿命和光离解通道等。碳负离子(1s22s12p4)的双重态比四重态稳定,(2s22p3)和(2s12p4)之间各辐射谱线波长位于超紫外区域的上限附近,其光谱强度很大的波长有6条,为研制X射线激光提供了有利的工作物质。