Probing molecular charge migration with high-harmonic sideband spectroscopy

Charge migration studies, which follow the coherent motion of electrons and holes in molecules in real time, are currently attracting much theoretical and experimental interest. In conjugated organic molecules, periodic charge migration motions emerge as attosecond solitons [1], with a localized hole that periodically travels back and forth across the target [2]. In this presentation, I will discuss recent theoretical efforts to probe these charge migration dynamics with high-harmonic sideband spectroscopy (HHSS) [3]. I will show how the time-dependent, migration-induced, modulation of the harmonic signal induces sidebands in high-harmonic spectra. In turn, these sidebands robustly encode information about the nature of the migration dynamics, which makes HHSS an all-optical, background-free, coherent probe. Finally, I will give an outlook on experimental applications of HHSS of charge migration.

[1] F. Mauger et al., Phys. Rev. Research 4, 013073 (2022).

[2] A.S. Folorunso et al., Phys. Rev. Lett. 126, 133002 (2021).

[3] K.A. Hamer et al., arXiv:2202.00730 (2022).