Some Emerging Opportunities in High-Harmonic Generation from Condensed Matter

Speaker: Jicai Zhang, The University of Hong Kong

Program Description
High-harmonic generation (HHG) from solids is a rapidly advancing field of research, enabling the exploration of electronic structure and ultrafast dynamics at unprecedented timescales. In this talk, I will present our latest work in time-resolved HHG spectroscopy when interacting with solid matter. Firstly, we demonstrate real-time probing of electron-phonon and anharmonic phonon-phonon coupling, along with their relaxation dynamics. Secondly, we showcase coherent manipulation of bandgap dynamics in a BaF2 crystal through precise control of the electron-phonon coupling using ultrashort light pulses. Lastly, we employ spatial- and time-resolved HHG spectroscopy to uncover the ponderomotive effect and the resulting dynamic Floquet-Bloch shift. These investigations provide valuable insights into fundamental processes, including carrier-carrier, carrier-phonon, and phonon-phonon interactions, offering exciting opportunities for understanding and manipulating such dynamics.

References:

1. Ferray. M, L'Huillier. A, Li. X. F., Lompre L. A., Mainfray. G, & Manus. V. Multiple-harmonic conversion of 1064 nm radiation in rare gases. Phys. B: At. Mol. Opt. Phys. 21(3), 31- 35. (1988).
2. Ghimire, S. et al. Observation of high-order harmonic generation in a bulk crystal. Nat. Phys. 7(2), 138-141 (2011).

3. Luu, T. T. et al. Extreme ultraviolet high-harmonic spectroscopy of solids. Nature 521(7553), 498-502 (2015).