Generation of helical topological exciton-polaritons

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 have been at deep cryogenic temperatures and under strong magnetic fields. We demonstrate helical topological polaritons up to 200 K without external magnetic field in monolayer WS2 excitons coupled to a non-trivial photonic crystal protected by pseudo time-reversal symmetry. The helical nature of the topological polaritons is verified where polaritons with opposite helicities are transported to opposite directions. Topological helical polaritons provide a platform for developing robust and tunable polaritonic spintronic devices for classical and quantum information processing applications.

Experimental observation of topological Z2 exciton-polaritons in transition metal dichalcogenide monolayers

“…We note that in a recent work the formation of edge exciton polaritons has been reported 77 due to hybridization of WS 2 excitons with the topological photonic states of a SiN metasurface. In our work we focus on a different scenario of strong coupling with bulk photonic modes, which gives rise to a transfer of topological invariant to bulk polaritonic states.…”

“…The resultant Z 2 type topological polaritonic phase gives rise to the formation of topological edge polaritons, whose dispersion asymptotically approaches bulk polaritonic bands. Interestingly, in the case of the interaction between photonic edge states and excitons 77 , the bulk states remain photonic, and the mechanism of edge polariton formation is different as it gives rise to the gapped character of edge polariton dispersion, with edge polaritons exhibiting one-way spin-polarized propagation. In the scenario considered here, we confirmed that for the case of hybridization of excitons with bulk photons, the edge polaritons emerge from the bulk upper polaritonic bands, in agreement with the bulk-boundary correspondence, which directly evidences the Z 2 topological polaritonic phase.…”

Recent Advances in Two‐Dimensional Heterostructures: From Band Alignment Engineering to Advanced Optoelectronic Applications

“…[ 122–126 ] In recent years, such methods are successfully expanded to 2D material systems, where various alloying 2D materials as well as composition grading 2D materials are successfully demonstrated. [ 127–142 ] At the same time, it also provides a broad material platform for the construction of heterostructures, where the introduction of alloying semiconductors with different bandgaps can effectively break through the limitation of material types, realizing heterostructures with continuously tunable band alignments. [ 85,110,143 ] Recently, through chemical vapor deposition approach, Zheng et al.…”

Hierarchical Microphase Behaviors of Chiral Block Copolymers under Kinetic and Thermodynamic Control

“…1,2 Deeply understanding the origination of chirality and thereby constructing chiral entities are intensely appealing in chemistry and materials science due to their intriguing optical and electronic properties. [3][4][5] Generally, bottom-up selfassembly of elaborately-designed molecules or building blocks with chiral features has been proven as an efficient route to fabricate chiral entities with hierarchical architectures at different length scales. [6][7][8] Block copolymers (BCPs) composed of helical segments (denoted as chiral block copolymers, BCPs*) are one of the ideal candidates for the bottom-up self-assembly, bringing various complicated chiral superstructures.…”