Fig. 3: The near-field response of individual scatterers at the wavelength of λ = 10.653 μm.
From: Strong in-plane scattering of acoustic graphene plasmons by surface atomic steps
a The near-field image of the sample region over a 2.6 μm × 2 μm area under the gate voltage of 2.9 V. The black dashed line and rectangle show the boundary and the selected scatterer area of the h-BN encapsulated single-layer graphene, respectively. Three obvious isolated scatterers are labeled as 1, 2, and 3 by arrows. Scale bar, 500 nm. b Near-field images of the acoustic graphene plasmons (AGPs) in the region of the black dashed square in (a) (the scatterer 1) at 2.9 and 2.2 V, respectively. The black dashed line represents the position where the detailed near-field closed to the scatterer is investigated in (d). Scale bar, 300 nm. c The fringe visibility (V) for the three different scatterers as a function of the gate voltages U. The errors bars show the fluctuation of ΔSS/ΔSR in different azimuthal directions close to the scatterers. d Comparison between the normalized near-field signal S4/S4,sub of the selected scatterer and the boundary of the graphene as a function of the voltages. The dashed and solid lines represent the scatterer and the boundary, respectively.
