Electronic Coherence and Coherent Dephasing in the Optical Control of Electrons in Graphene
Electronic Coherence and Coherent Dephasing in the Optical Control of Electrons in Graphene
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DOI：
10.1021/acs.nanolett.1c02538
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发表时间：
2021-11-24
期刊：
影响因子：
10.8
通讯作者：
Hommelhoff, Peter
中科院分区：
文献类型：
--
作者：
Heide, Christian;Eckstein, Timo;Hommelhoff, Peter
电子相干对于量子力学固体性质的获取和控制至关重要。利用纯电子可观察到的光电流，我们测量了石墨烯中电子相干时间的下限为22 +/- 4 fs。光电流是测量电子相干性的理想选择，因为它是相干量子路径干涉的直接结果，由两个超短双色激光脉冲之间的延迟控制。第一脉冲注入的居群幅度与第二脉冲产生的居群幅度之间的干扰干扰的最大延迟决定了电子相干时间。特别是，数值模拟显示，实验数据产生了电子相干时间的下界，由于石墨烯中的宽带吸收而被相干减相掩盖。我们期望我们的结果将显著促进对从弱场激发到强驱动系统的固态系统中相干量子控制的理解。
Electronic coherence is of utmost importance for the access and control of quantum-mechanical solid-state properties. Using a purely electronic observable, the photocurrent, we measure a lower bound of the electronic coherence time of 22 +/- 4 fs in graphene. The photocurrent is ideally suited to measure electronic coherence, as it is a direct result of coherent quantum-path interference, controlled by the delay between two ultrashort two-color laser pulses. The maximum delay for which interference between the population amplitude injected by the first pulse interferes with that generated by the second pulse determines the electronic coherence time. In particular, numerical simulations reveal that the experimental data yields a lower bound on the electronic coherence time, masked by coherent dephasing due to the broadband absorption in graphene. We expect that our results will significantly advance the understanding of coherent quantum control in solid-state systems ranging from excitation with weak fields to strongly driven systems.