Visualizing and controlling vibrational wave packets of single molecules
Visualizing and controlling vibrational wave packets of single molecules
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DOI：
10.1038/nature09110
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发表时间：
2010-06-17
期刊：
影响因子：
64.8
通讯作者：
Van Hulst, Niek F.
中科院分区：
文献类型：
--
作者：
Brinks, Daan;Stefani, Fernando D.;Van Hulst, Niek F.
化学反应所采取的路径的主动操纵和能量转换过程的优化（1-3）提供了通过使用成形激光脉冲相干控制量子干涉的引人注目的例子。在实验上，相干性通常通过使系综中的分子子集（4-7）与超短激光脉冲（8）同步来建立。但在复杂的系统中，即使化学性质相同的分子也存在不同的构象和不同的环境，同步子集将具有内在的不均匀性，这限制了可以实现的相干控制的程度。克服内在不均匀性的一个自然的，实际上也是最终的解决方案是一次研究一个分子的行为。单分子方法（9，10）为生物分子相互作用（11-13），细胞过程（14）和过冷液体（15）和共轭聚合物（16）的动力学等各种现象提供了有用的见解。迄今为止，单分子的相干态制备仅限于低温条件（17），而在室温下，仅探测了非相干振动弛豫路径（18）。在这里，我们报告的观察和操作的振动波包干涉在单个分子在环境条件下。我们表明，适应的时间和相位分布的光激发场的每个分子的动态结果在一个高度的控制，并期望该方法可以扩展到实现单分子相干控制在其他复杂的非均匀系统。
The active steering of the pathways taken by chemical reactions and the optimization of energy conversion processes(1-3) provide striking examples of the coherent control of quantum interference through the use of shaped laser pulses. Experimentally, coherence is usually established by synchronizing a subset of molecules in an ensemble(4-7) with ultra-short laser pulses(8). But in complex systems where even chemically identical molecules exist with different conformations and in diverse environments, the synchronized subset will have an intrinsic inhomogeneity that limits the degree of coherent control that can be achieved. A natural-and, indeed, the ultimate-solution to overcoming intrinsic inhomogeneities is the investigation of the behaviour of one molecule at a time. The single-molecule approach(9,10) has provided useful insights into phenomena as diverse as biomolecular interactions(11-13), cellular processes(14) and the dynamics of supercooled liquids(15) and conjugated polymers(16.) Coherent state preparation of single molecules has so far been restricted to cryogenic conditions(17), whereas at room temperature only incoherent vibrational relaxation pathways have been probed(18). Here we report the observation and manipulation of vibrational wave-packet interference in individual molecules at ambient conditions. We show that adapting the time and phase distribution of the optical excitation field to the dynamics of each molecule results in a high degree of control, and expect that the approach can be extended to achieve single-molecule coherent control in other complex inhomogeneous systems.