By combining a synchrotron source scattering type, scanning near-field optical microscopy (s-SNOM), SINS achieves chemical selectivity spanning the entire mid- and far-infrared regions with < 25 nm spatial resolution.
H.A. Bechtel et al. Proceedings of the National Academy of Sciences, 111(20), 7191–7196 (2014)
(a) CaCO3 polymorph heterogeneity in a polished M. edulis shell. (b) AFM topography in the interface region of calcite (Left), appearing with a globular morphology, and aragonite (Right), appearing as stacked tablets. The green line indicates the interface between calcite and aragonite. (c) SINS spectra of calcite (blue) and aragonite (red) acquired at the location of the blue and red circles, respectively, in A. (Insets) Zoom-in of ν2 mode (gray box) with the dashed lines indicating the peak positions. (d) Spatio-spectral SINS linescan plot across the solid white line in (b).