(color online) Optical nano-imaging of graphene ribbons. (a) Upper panel: topological image of a graphene ribbon; middle panel: near-field image; lower panel: topological and near-field signal profiles extracted from the above images, with positions indicated by the black line in the topological image and the red line in the near-field image, respectively. The scale bar is 500 nm and the wavelength of incident light is 9.68 μm. (b) Left: topological and near-field images of graphene ribbon with wrinkles in the top and bottom panels, respectively; right panels: topological and near-field signal profiles extracted from the left. The topological profile is indicated by the black line, and the optical signal profiles are indicated by the red and orange lines in the near-field image. The scale bar is 500 nm and the wavelength of incident light is 9.68 μm. (c) Upper panel: topological image of a graphene ribbon; middle panel: near-field optical imaging; lower panel: the topological and near-field signal profiles are indicated by the black line in the topological image and the red line in the optical image, respectively. The scale bar is 1 μm and the incident wavelength is 10.15 μm.