Signatures and control of strong-field dynamics in a complex system
Signatures and control of strong-field dynamics in a complex system
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DOI：
10.1073/pnas.1509201112
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发表时间：
2015-12
期刊：
影响因子：
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通讯作者：
K. Meyer;Zuoye Liu;N. Müller;J. Mewes;A. Dreuw;T. Buckup;M. Motzkus;T. Pfeifer
中科院分区：
文献类型：
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作者：
K. Meyer;Zuoye Liu;N. Müller;J. Mewes;A. Dreuw;T. Buckup;M. Motzkus;T. Pfeifer
意义使用强激光控制复杂分子是科学界长期以来的梦想。在这篇文章中，我们提出了一种利用强激光场测量和控制复杂分子量子态的物理概念。特别是，我们证明了激发分子态的量子力学相可以被强激光操纵，这是完全(幅度和相位)控制分子量子态的一个关键量。借助时间分辨吸收光谱实验和强度分辨吸收光谱实验，我们将这一概念应用于溶液中大分子染料的动力学。因此，所展示的相位控制概念代表着朝着激光化学的最终目标的重大飞跃。用光控制化学反应，即用强场激光以所需的方式选择性地形成和断裂化学键，是科学界长期以来的梦想。实现这一目标的关键一步是了解原子和分子系统与强激光的相互作用。到目前为止，进行的实验主要集中在量子态布居的变化上。利用不同路径的量子干涉，利用位相整形激光脉冲来控制末态的布居。然而，这些最终状态的量子力学阶段，控制着系统的响应，从而控制着随后的系统时间演化和动力学，并没有得到系统的分析。在这里，我们演示了复杂系统在液体中的广义相控概念。在该方案中，控制激光脉冲的强度作为控制旋钮来操纵激发态的量子力学相变。这种控制表现在分子的偶极响应的阶段，通过其吸收光谱可以到达。正如这里所报道的，对于从弱微扰到强场的激光脉冲强度，宽分子吸收带的形状被显著地改变。这一广义的相控概念为解释和理解大分子在外加脉冲激光场中的强场动力学和控制提供了有力的工具。
Significance Using intense lasers to control complex molecules is a long-held dream in science. In this article, we develop a physics concept for measuring and controlling the quantum states of complex molecules by strong laser fields. We show that, in particular, the quantum-mechanical phase of excited molecular states can be manipulated by the intense laser, a key quantity for full (amplitude and phase) control of molecular quantum states. With the help of time- and intensity-resolved absorption spectroscopy experiments, we apply this idea to the dynamics of a large dye molecule in solution. The demonstrated phase-control concept thus represents a major leap toward the ultimate goal of laser chemistry. Controlling chemical reactions by light, i.e., the selective making and breaking of chemical bonds in a desired way with strong-field lasers, is a long-held dream in science. An essential step toward achieving this goal is to understand the interactions of atomic and molecular systems with intense laser light. The main focus of experiments that were performed thus far was on quantum-state population changes. Phase-shaped laser pulses were used to control the population of final states, also, by making use of quantum interference of different pathways. However, the quantum-mechanical phase of these final states, governing the system’s response and thus the subsequent temporal evolution and dynamics of the system, was not systematically analyzed. Here, we demonstrate a generalized phase-control concept for complex systems in the liquid phase. In this scheme, the intensity of a control laser pulse acts as a control knob to manipulate the quantum-mechanical phase evolution of excited states. This control manifests itself in the phase of the molecule’s dipole response accessible via its absorption spectrum. As reported here, the shape of a broad molecular absorption band is significantly modified for laser pulse intensities ranging from the weak perturbative to the strong-field regime. This generalized phase-control concept provides a powerful tool to interpret and understand the strong-field dynamics and control of large molecules in external pulsed laser fields.