Generation of helical topological exciton-polaritons

TLDR

Topological photonics in strongly coupled light‑matter systems promises tunable, disorder‑robust optical devices, yet experimental realization of topological polaritons has so far required deep cryogenic temperatures and strong magnetic fields. The study demonstrates helical topological polaritons up to 200 K without an external magnetic field in monolayer WS₂ excitons coupled to a photonic crystal protected by pseudo time‑reversal symmetry. This is achieved by coupling monolayer WS₂ excitons to a nontrivial photonic crystal that preserves pseudo time‑reversal symmetry. The helical polaritons, with opposite helicities propagating in opposite directions, were experimentally verified and provide a platform for robust, tunable polaritonic spintronic devices in classical and quantum information processing.

Abstract

Topological photonics in strongly coupled light-matter systems offer the possibility for fabricating tunable optical devices that are robust against disorder and defects. Topological polaritons, i.e., hybrid exciton-photon quasiparticles, have been proposed to demonstrate scatter-free chiral propagation, but their experimental realization to date has been at deep cryogenic temperatures and under strong magnetic fields. We demonstrate helical topological polaritons up to 200 kelvin without external magnetic field in monolayer WS2 excitons coupled to a nontrivial photonic crystal protected by pseudo time-reversal symmetry. The helical nature of the topological polaritons, where polaritons with opposite helicities are transported to opposite directions, is verified. Topological helical polaritons provide a platform for developing robust and tunable polaritonic spintronic devices for classical and quantum information-processing applications.