Fig. 1: Structure and the near-field response of an acoustic graphene plasmon (AGP) device.
From: Strong in-plane scattering of acoustic graphene plasmons by surface atomic steps
a Schematic of the AGP device, which is composed of h-BN (2 nm)/graphene/h-BN (6 nm) heterostructure placed on Au (50 nm)/SiO2 (300 nm)/Si substrate. The inset shows the cross-section view of the AGP device. b Real space near-field image of the AGPs at −2 V, the color bar represents the normalized intensity. c The amplitude of the Fourier transformation of (b) in momentum space (kx, ky). d The comparison between the wavelength and back gate voltage-dependent dispersion of AGPs and that of graphene plasmons (GPs). The dispersion was obtained by caculating the imaginary of the reflection coefficient (Im(rp)) with the transfer matrix method. The white circles represent the experimental results. The error bars show the width of the concentric circles in momentum space. e, f Near-field image of the AGPs at −4 V and the corresponding Fourier transform. The wavelength of excitation light is λ = 10.653 μm. Scale bars, 300 nm.
