Surface plasmons in graphene have many promising properties, such as high confinement, low losses, and gate-tunability. However, it is also the high confinement that makes them difficult to excite due to their large momentum mismatch with free-space mid-infrared light. We propose to use shaped graphene nano-vacancies to compensate for the momentum mismatch, revealing its high flexibility in graphene plasmon (GP) excitation and manipulation. We first examine the electromagnetic standing waves generated with a pair of straight vacancies, in order to verify the excitation of GPs and to illustrate their tunability with gate voltage. Plasmonic lenses are then designed to achieve the super-focusing of mid-infrared light and to generate plasmonic vortices in graphene.
© 2014 Optical Society of America
Original Manuscript: November 12, 2013
Revised Manuscript: January 26, 2014
Manuscript Accepted: January 28, 2014
Published: March 11, 2014
Luping Du and Dingyuan Tang, "Manipulating propagating graphene plasmons at near field by shaped graphene nano-vacancies," J. Opt. Soc. Am. A 31, 691-695 (2014)