Tuning excitonic quantum optics in stacked van-der-Waals semiconductors

Principal investigators

  1. Kai-Qiang Lin, University of Regensburg, kaiqiang.lin (at) physik.uni-regensburg.de [webpage]
  2. Sebastian Bange, University of Regensburg, sebastian.bange (at) physik.uni-regensburg.de [webpage]

teaser picture


The formation of excitons in transition-metal dichalcogenide (TMDC) monolayers at energies near twice fundamental band-edge excitons is a new and exciting discovery, and can be exploited for laser-driven excitonic quantum interference. Within the project, we will systematically study how the excitonic quantum interference phenomenon can be controlled in artificial van-der-Waals (vdW) bilayers and multilayers based on TMDCs and TMDC/ferromagnet heterostructures - through band hybridization and proximity effects. We will explore the valley selectivity of the excitonic quantum interference in vdW homo- and heterostructures, and further apply it to study the effect of the moiré superlattice.

When driven by femtosecond laser pulses, interference occurs under dual resonance when the energy needed to drive the low-energy exciton is nearly degenerate with the promotion of the electron further into the higher conduction band. The interference is probed as spectral dips – electromagnetically induced transparency – in the second-harmonic generation.