title: Splashing transients of 2D plasmons launched by swift electrons.
abstract: Launching of plasmons by swift electrons has long been used in electron energy-loss spectroscopy (EELS) to investigate the plasmonic properties of ultrathin, or two-dimensional (2D), electron systems. However, the question of how a swift electron generates plasmons in space and time has never been answered. We address this issue by calculating and demonstrating the spatial-temporal dynamics of 2D plasmon generation in graphene. We predict a jet-like rise of excessive charge concentration that delays the generation of 2D plasmons in EELS, exhibiting an analog to the hydrodynamic Rayleigh jet in a splashing phenomenon before the launching of ripples. The photon radiation, analogous to the splashing sound, accompanies the plasmon emission and can be understood as being shaken off by the Rayleigh jet-like charge concentration. Considering this newly revealed process, we argue that previous estimates on the yields of graphene plasmons in EELS need to be reevaluated.
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China.; Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Xiao
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Ido
authors.identifier: 0000-0003-2691-1892
authors.initials: I
authors.lastname: Kaminer
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Xihang
authors.initials: X
authors.lastname: Shi
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Zhaoju
authors.identifier: 0000-0002-9880-2655
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Gao
authors.affiliation: Department of Physics, University of Zagreb, Bijenička c. 32, 10000 Zagreb, Croatia.
authors.forename: Hrvoje
authors.identifier: 0000-0002-9808-6628
authors.initials: H
authors.lastname: Buljan
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Joannopoulos
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Marin
authors.identifier: 0000-0001-8466-0193
authors.initials: M
authors.lastname: Soljačić
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Chen
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.; Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Baile
authors.initials: B
authors.lastname: Zhang
keywords: 2D plasmons; EELS; Reyleigh jet; formation time; formation zone; graphene; splashing; transition radiation