Fig. 3: Scanning near-field optical microscopy measurements.
From: Extremely confined gap plasmon modes: when nonlocality matters
a Schematic illustration of the s-SNOM setup (see “Methods” for details). Pseudo-color images of (b) amplitude and (c) real-part of the detected near-field (NF) signal for the sample with 3 nm dielectric gap at λ0 = 1550 nm excitation wavelength (scale bars: 2 μm). d Amplitude of the Fourier transformed NF map along the propagation coordinate (x → kx) and (e) its profile (averaged along the y-axis).
