Figure 2: Nano-FTIR study of a 1,723 nm long linear h-BN antenna on SiO₂.

(a) Experimental and (b) simulated nano-FTIR amplitude spectra. They were obtained at the two positions marked by the red and blue dots in c, and normalized to the nano-FTIR spectrum of a gold film. For clarity, the spectra have been vertically shifted by the indicated values. The white background colour indicates the reststrahlen band. (c) AFM topography image of the antenna. The antenna has a thickness of 74 nm (measured from the AFM image). Its average width and height were measured by electron microscopy and amount to 190 nm and 1,723 nm, respectively (see Supplementary Fig. 1). Scale bar, 200 nm. (d) Experimental and (e) simulated spectral line scan along the dashed green line in c. Open and solid symbols mark the resonances analysed in Fig. 3b.