title: Unidirectional excitation of graphene plasmons in Au-graphene composite structures by a linearly polarized light beam.
abstract: Controllable manipulation of propagating surface plasmon polaritons is critical in plasmonics and important for nanophotonic applications. Here, we demonstrate theoretically that graphene plasmons (GPs) can be unidirectionally excited in an Au-graphene composite structure by a linearly polarized optical wave at the wavelength of 10.2 µm. The unidirectional ratio can reach as large as 900 with the incidence angle at 37.7° off normal, which is obtained by the angular spectrum of GPs. Moreover, the physical mechanism behind the unidirectional excitation is revealed to be the interference between anti-symmetric and symmetric amplitude distributions of GPs, which are induced by the gold rod antenna under the normal and grazing illuminations, respectively.
authors.forename: Zenghong
authors.initials: Z
authors.lastname: Ma
authors.forename: Wei
authors.initials: W
authors.lastname: Cai
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Yinxiao
authors.initials: Y
authors.lastname: Xiang
authors.forename: Mengxin
authors.initials: M
authors.lastname: Ren
authors.forename: Xinzheng
authors.initials: X
authors.lastname: Zhang
authors.forename: Jingjun
authors.initials: J
authors.lastname: Xu