采用分子动力学方法,研究了金属Ag固液界面在固化过程中的动力学过程及缺陷俘获。结果发现,金属Ag的界面温度存在某个特征值(T^*),生长速度在这个特征温度附近达到最大值。同时发现液体在产生晶体时缺陷以空位为主。计算结果表明,缺陷浓度与界面温度之间存在线性关系,缺陷浓度随着界面温度的降低而逐渐增大,在特征温度附近发生转变。同时发现缺陷浓度与生长速度相关,当界面温度高于特征温度(T>T^*)时,二者存在近似线性关系且与方向无关,但当界面温度低于特征温度(T^*)时,(100)方向和(110)方向存在着明显的各向异性,表明缺陷俘获与生长机制转变有关。

We demonstrate that a finite number of nano-slits can realize beam splitting and focusing of light by coating the metallic film surfaces with nonlinear Kerr medium. The numerical simulation shows that the beam splitting and focusing can be controlled by the incident light intensity. The splitting angle is quasi-periodically modulated by the incident light intensity, and the focusing length of forward propagating transmitted light decreases as the incident light intensity increases. These effects are explained by the surface plasmon polariton Bloch modes and self-focusing theory.

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.

The property of femtosecond laser pulse propagation in a metallic nano-slit lens, which is composed of nano-slits with variant widths, is investigated by using the finite-difference time-domain method. By appropriately setting the width profile of the arrayed nano-slits, we find that the femtosecond laser pulse can be focused on a nano-scale spot, while the pulse shape is well maintained beyond the spot location.