Spectroscopic s-SNOM powered by infrared frequency-combs

We report the application of a new type of Fourier-transform spectroscopy called coherent frequency-comb FTIR. This new spectrometer is used to illuminate and read out a scanning mid-infared near-field microscope. The latter is based on an AFM with commercial, cantilevered tips and works on the principle of light scattering; thus it is named scattering or s-SNOM. As a result, we obtain mid-infrared spectra for each pixel of the scanned image. The spatial resolution is typically 30 nm, but 10 nm appears feasible in the near future.