Doping-driven topological polaritons in graphene/α-MoO3 heterostructures

Hai Hu*, Na Chen, Hanchao Teng, Renwen Yu, Yunpeng Qu, Jianzhe Sun, Mengfei Xue, Debo Hu, Bin Wu, Chi Li, Jianing Chen, Mengkun Liu, Zhipei Sun, Yunqi Liu, Peining Li, Shanhui Fan, F. Javier García de Abajo, Qing Dai

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)
11 Downloads (Pure)

Abstract

Control over charge carrier density provides an efficient way to trigger phase transitions and modulate the optoelectronic properties of materials. This approach can also be used to induce topological transitions in the optical response of photonic systems. Here we report a topological transition in the isofrequency dispersion contours of hybrid polaritons supported by a two-dimensional heterostructure consisting of graphene and α-phase molybdenum trioxide. By chemically changing the doping level of graphene, we observed that the topology of polariton isofrequency surfaces transforms from open to closed shapes as a result of doping-dependent polariton hybridization. Moreover, when the substrate was changed, the dispersion contour became dominated by flat profiles at the topological transition, thus supporting tunable diffractionless polariton propagation and providing local control over the optical contour topology. We achieved subwavelength focusing of polaritons down to 4.8% of the free-space light wavelength by using a 1.5-μm-wide silica substrate as an in-plane lens. Our findings could lead to on-chip applications in nanoimaging, optical sensing and manipulation of energy transfer at the nanoscale.

Original languageEnglish
Article numberARTN s41565-022-01185-2
Pages (from-to)940-946
Number of pages7
JournalNature Nanotechnology
Volume17
Issue number9
Early online date18 Aug 2022
DOIs
Publication statusPublished - Sep 2022
MoE publication typeA1 Journal article-refereed

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