title: Ultraconfined Plasmonic Hotspots Inside Graphene Nanobubbles.
abstract: We report on a nanoinfrared (IR) imaging study of ultraconfined plasmonic hotspots inside graphene nanobubbles formed in graphene/hexagonal boron nitride (hBN) heterostructures. The volume of these plasmonic hotspots is more than one-million-times smaller than what could be achieved by free-space IR photons, and their real-space distributions are controlled by the sizes and shapes of the nanobubbles. Theoretical analysis indicates that the observed plasmonic hotspots are formed due to a significant increase of the local plasmon wavelength in the nanobubble regions. Such an increase is attributed to the high sensitivity of graphene plasmons to its dielectric environment. Our work presents a novel scheme for plasmonic hotspot formation and sheds light on future applications of graphene nanobubbles for plasmon-enhanced IR spectroscopy.
authors.affiliation: Department of Physics, University of California, San Diego , La Jolla, California 92093, United States.|Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States.|Department of Physics and Astronomy, Iowa State University , Ames, Iowa 50011, United States.
authors.forename: Z
authors.initials: Z
authors.lastname: Fei
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States.|Department of Chemistry, William Paterson University , Wayne, New Jersey 07470, United States.
authors.forename: J J
authors.initials: JJ
authors.lastname: Foley
authors.affiliation: Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States.|Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: W
authors.initials: W
authors.lastname: Gannett
authors.affiliation: Department of Physics, University of California, San Diego , La Jolla, California 92093, United States.|Department of Physics and Astronomy, Stony Brook University , Stony Brook, New York 11794, United States.
authors.forename: M K
authors.initials: MK
authors.lastname: Liu
authors.affiliation: Department of Physics, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: S
authors.initials: S
authors.lastname: Dai
authors.affiliation: Department of Physics, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: G X
authors.initials: GX
authors.lastname: Ni
authors.affiliation: Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States.|Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: A
authors.initials: A
authors.lastname: Zettl
authors.affiliation: Department of Physics, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: M M
authors.initials: MM
authors.lastname: Fogler
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: G P
authors.initials: GP
authors.lastname: Wiederrecht
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: S K
authors.initials: SK
authors.lastname: Gray
authors.affiliation: Department of Physics, University of California, San Diego , La Jolla, California 92093, United States.|Department of Physics, Columbia University , New York, New York 10027, United States.
authors.forename: D N
authors.initials: DN
authors.lastname: Basov
keywords: FDTD simulation; Graphene nanobubbles; heterostructures; nanoinfrared imaging; plasmon hotspots