Peschel Martin T, Högner Maximilian, Buberl Theresa, Keefer Daniel, de Vivie-Riedle Regina, Pupeza Ioachim
Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377, Munich, Germany.
Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748, Garching, Germany.
Nat Commun. 2022 Oct 6;13(1):5897. doi: 10.1038/s41467-022-33477-5.
The evolution of ultrafast-laser technology has steadily advanced the level of detail in studies of light-matter interactions. Here, we employ electric-field-resolved spectroscopy and quantum-chemical modelling to precisely measure and describe the complete coherent energy transfer between octave-spanning mid-infrared waveforms and vibrating molecules in aqueous solution. The sub-optical-cycle temporal resolution of our technique reveals alternating absorption and (stimulated) emission on a few-femtosecond time scale. This behaviour can only be captured when effects beyond the rotating wave approximation are considered. At a femtosecond-to-picosecond timescale, optical-phase-dependent coherent transients and the dephasing of the vibrations of resonantly excited methylsulfonylmethane (DMSO) are observed. Ab initio modelling using density functional theory traces these dynamics back to molecular-scale sample properties, in particular vibrational frequencies and transition dipoles, as well as their fluctuation due to the motion of DMSO through varying solvent environments. Future extension of our study to nonlinear interrogation of higher-order susceptibilities is fathomable with state-of-the-art lasers.
超快激光技术的发展稳步提升了光与物质相互作用研究的细节水平。在此，我们采用电场分辨光谱和量子化学建模，精确测量并描述了倍频程跨度的中红外波形与水溶液中振动分子之间完整的相干能量转移。我们技术的亚光周期时间分辨率揭示了在几飞秒时间尺度上交替出现的吸收和（受激）发射。只有在考虑超越旋转波近似的效应时，才能捕捉到这种行为。在飞秒到皮秒的时间尺度上，观察到了光学相位相关的相干瞬态以及共振激发的二甲基亚砜（DMSO）振动的退相。使用密度泛函理论的从头算建模将这些动力学追溯到分子尺度的样品特性上，特别是振动频率和跃迁偶极矩，以及由于DMSO在不同溶剂环境中的运动而产生的波动。利用最先进的激光，我们的研究未来扩展到对高阶极化率的非线性探测是可行的。
