用强laser脉冲操纵分子的扭转

实现和应用laser控制分子扭转的实验与理论研究

A combined experimental and theoretical study on realizing and using laser controlled torsion of molecules

研究了强激光脉冲作用下3，5-二氟-3 '，5'-二溴联苯（DFDBrBPh）分子的扭转运动。纳秒激光脉冲在空间上对齐立体碳-碳（C-C）键轴，允许垂直偏振的强飞秒脉冲引发伴随着围绕固定轴的旋转的扭转运动。我们通过飞秒时间分辨库仑爆炸成像来监测诱导运动。我们的理论分析证实了实验结果，并在此基础上讨论了激光诱导扭转的未来应用，即，基于扭转分子的去消旋化和激光控制分子结的时间分辨研究。

Manipulating quantum wave packets via time-dependent absorption

A pulse of matter waves may dramatically change its shape when traversing an absorbing barrier with time-dependent transparency. Here we show that this effect can be utilized for controlled manipulation of spatially-localized quantum states. In particular, in the context of atom-optics experiments, we explicitly demonstrate how the proposed approach can be used to generate spatially shifted, split, squeezed and cooled atomic wave packets. We expect our work to be useful in devising new interference experiments with atoms and molecules and, more generally, to enable new ways of coherent control…

啁啾飞秒laser脉冲对磁光阱中超冷分子动力学的相干控制

Coherent control of ultracold molecule dynamics in a magneto-optical trap using chirped femtosecond laser pulses

研究了啁啾飞秒激光脉冲对Rb磁光阱中超冷分子形成的影响。我们已经发现，啁啾飞秒脉冲的应用抑制了85 Rb-2和87 Rb-2最低三重态分子的形成，与可比的非啁啾脉冲，连续照明，和背景形成率。啁啾量的变化表明，这种抑制是相干的性质，这表明相干控制可能是有用的操纵超冷量子分子气体的动力学。

通过整形飞秒强激光脉冲以阿秒精度控制电子运动

Controlling electron motion with attosecond precision by shaped femtosecond intense laser pulse

本文提出时间双缝干涉仪方案，通过整形飞秒激光脉冲精确测量电场并控制电子隧穿波包，实现阿秒精度的电子亚周期动力学控制，并经量子轨迹蒙特卡罗和三维含时薛定谔方程验证。

Manipulating Twisted Electrons in Strong-Field Ionization

We investigate the discrete orbital angular momentum (OAM) of photoelectrons freed in strongfield ionization. We use these `twisted' electrons to provide an alternative interpretation on existing experimental work of vortex interferences caused by strong field ionization mediated by two counterrotating circularly polarized pulses separated by a delay. Using the strong field approximation, we derive an interference condition for the vortices. In computations for a neon target we find very good agreement of the vortex condition with photoelectron momentum distributions computed with the strong f…

Quantum Control of Photodissociation via Manipulation of Bond Softening

We present a method to control photodissociation by manipulating the bond softening mechanism occurring in strong shaped laser fields, by varying the chirp sign and magnitude of an ultra-short laser pulse. Manipulation of bond-softening is experimentally demonstrated for strong field (795 nm, 10^12 - 10^13 W/cm^2) photodissociation of H2+, exhibiting substantial increase of dissociation by positively chirped pulses with respect to both negatively chirped and transform limited pulses. The measured kinetic energy release and angular distributions are used to quantify the degree of control of dis…