In this work we investigate plasmons in high-quality graphene boron nitride heterostructures. We find unprecedented low damping and strong field confinement of graphene plasmons and identify and characterize the main damping mechanisms in these heterostructures.

Graphene plasmonics provides an excellent new platform for strong optical field confinement with relatively low damping. This enables new device classes for deep subwavelength metamaterials, single-photon nonlinearities, extraordinarily strong light-matter interactions and nano-optoelectronic switches.

We show results where we exploit scattering-type scanning near-field optical microscopy to image propagating plasmons in such high quality graphene devices encapsulated between boron nitride. Frequency dispersion and particularly plasmon damping in real space is determined and we show that these high quality graphene samples show unprecedented low graphene plasmon damping combined with extremely strong field confinement. We identify the main damping channels to be intrinsic thermal phonons in the graphene as well as dielectric losses in the h-BN. The low obtained damping as well as the theoretical understanding of the damping mechanisms are the key for the development of graphene nano-photonic and nano-optoelectronic devices.


Thursday, February 19, 2015, 17:00. Seminar Room