| Time：1140226 (Wed.) 14:20~16:20 Speaker：Prof.楊超強(Chaw-Keong Yong) 國立臺灣大學物理學系/Department of Physics, National Taiwan University Title：Optical manipulation of quantum phenomena in low-dimensional systems. Abstract： Low-dimensional systems provide an excellent platform to test the concepts arising from light-induced quantum phenomena. In-particular, strong electronic wavefunction confinement and prominent light-matter interactions open up new avenue to explore nonequilibrium electron dynamics beyond the classical limits. In this talk, I will present two complementary strategies for controlling many-body quantum phenomena in low-dimensional semiconducting systems through the development of femtosecond laser spectroscopy. First, I will show how Floquet engineering breaks-down the classical atomic Fano limits and enables widely tunable Fano quantum interference in semiconducting carbon nanotubes. By femtosecond-laser-driven manipulation of discrete phonon Raman scattering pathways, we achieve continuous tuning of Fano quantum interference from antiresonant, to dispersive, and to Lorentzian lineshapes, with large modulations in the Fano parameter. Adjusting laser intensity further shifts the Floquet resonance and switch the quantum interference strength from destructive to constructive. Second, we demonstrate optical engineering of strongly correlated bosonic states in a WS2/WSe2 moiré superlattices heterostructure. Time-resolved spectroscopy reveals a new resonance ~27 meV above the ground state, appearing only when exciton density surpasses one per moiré cell. This strongly correlated two-exciton state exhibits substantially faster recombination and collective valley depolarization dynamics, highlighting unprecedented optical control over many-body exciton-exciton correlations using photons. Place：S101, Gongguan Campus, NTNU |
