Host: Prof. Nanlin Wang
Venue: TDLI Meeting Room N400
Tencent Meeting link: https://meeting.tencent.com/dm/jpnJymsE4usG
Meeting ID: 537766126, no password
Abstract:
Precise photon manipulation at the nanoscale is a key research direction in information technology. Polaritons—hybrid light–matter excitations—in 2D materials provide unique opportunities for controlling light at nanoscales. Here we report a novel mechanism for nanoscale polariton manipulation based on superlattices of domain wall solitons in 2D moiré systems. In twisted bilayer graphene on boron nitride, we demonstrate on-off switching and continuous tuning of local polariton-soliton interactions with a critical yet unexplored degree of freedom—the soliton angle that characterizes the local strain direction. We show that such tunability arises from dramatic modifications of topological as well as conventional soliton states by local soliton angle. Furthermore, we reveal the capability of these structures to spatially modify the near-field profile, phase and propagation direction of polaritons in record small footprints, enabling generation and electrical switching of directional polaritons. Our results unlock the enormous potential of 2D moiré materials to serve as gradient polaritonic surfaces with spatially tailored light-matter interactions, opening up new avenues for nanoscale spatial polariton engineering and for exploring novel photonic physics in moiré soliton superlattices.
Biography:
Zhiqiang Li is a Professor and Vice Dean of the College of Physics, Sichuan University. His research mainly focuses on low-dimensional quantum systems, quantum nanophotonics. He has made a series of achievements in novel 2D materials, topological insulators,many-body effects, etc. He has published more than 60 papers including Nature Physics, Nature Communications, Science Advances, and Physical Review Letters.