Material-agnostic, robust non-resonant schemes for creating light-induced Chern insulators have been theoretically developed, using light with polarization states tailored to the symmetry of the lattice. The schemes were shown to work for various graphene-like materials – both pristine graphene and gapped systems. Detailed analysis was done for pristine graphene, hexagonal Boron Nitride, and MoS2. Generation of valley-selective excitations in all of these materials has been theoretically found.
Our investigation has shown that even linearly polarized fields have been found to generate valley-selective excitation and light-induced topology in graphene-type materials. In particular, the impact of the orbital angular momentum of light on the topological state of a 2D quantum material has been analysed and a new scheme for Chern number engineering has been theoretically developed. The scheme explicitly takes advantage of controlled OAM of a light beam.
As observable, high harmonic generation has been shown to provide sub-femtosecond-resolved information about light-induced topological state and valley-selective excitations. Interestingly, and somewhat unexpectedly, high harmonic radiation generated in intense light-matter interaction was found to have quantum photon statistics that reflects the quantum system dynamics, suggesting a possible new route for mapping out quantum material response.
Experimental work included establishing a framework to prepare and to diagnose quantum materials, setup of cutting-edge light sources with waveform control and polarization patterning capabilities, setup and test of new diagnostics methodologies that are field sensitive. Angle-resolved high-harmonic photoelectron spectroscopy established new experimental observables for probing topological properties.
Unexpected and unforeseen results: A new type of light -- synthetic chiral light -- has been found to arise from the presence of longitudinal field component in multi-color structured vortex beams. These beams are envisioned as the key tool for patterning light-induced topology. The unique properties of this light in the interaction with chiral matter have been identified, leading to giant enantio-sensitive signals.
The work performed so far resulted in publications in high-profile journals: Nature Physics, Nature Photonics, Nature Communications, Optica.
