Plasmon-induced optical anisotropy in hybrid graphene-metal nanoparticle systems.
Hybrid plasmonic metal-graphene systems are emerging as a class of optical metamaterials that facilitate strong light-matter interactions and are of potential importance for hot carrier graphene-based light harvesting and active plasmonic applications. Here we use femtosecond pump-probe measurements to study the near-field interaction between graphene and plasmonic gold nanodisk resonators. By selectively probing the plasmon-induced hot carrier dynamics in samples with tailored graphene-gold interfaces, we show that plasmon-induced hot carrier generation in the graphene is dominated by direct photoexcitation with minimal contribution from charge transfer from the gold. The strong near-field interaction manifests as an unexpected and long-lived extrinsic optical anisotropy. The observations are explained by the action of highly localized plasmon-induced hot carriers in the graphene on the subresonant polarizability of the disk resonator. Because localized hot carrier generation in graphene can be exploited to drive electrical currents, plasmonic metal-graphene nanostructures present opportunities for novel hot carrier device concepts.
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.
Adam M
AM
Gilbertson
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.
Yan
Y
Francescato
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.
Tyler
T
Roschuk
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.
Viktoryia
V
Shautsova
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.|‡Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive, 117576 Singapore.
Yiguo
Y
Chen
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.
Themistoklis P H
TP
Sidiropoulos
‡Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive, 117576 Singapore.
Minghui
M
Hong
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.
Vincenzo
V
Giannini
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.
Stefan A
SA
Maier
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.
Lesley F
LF
Cohen
†Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ, United Kingdom.
Rupert F
RF
Oulton
Graphene; anisotropy; hot carrier; hybrid; plasmonic; pump−probe