Infrared devices 1 Infrared radiation 1 Interferometry 1 Localised 1 Nanostructures 1 Optical resolving power 1 Phonons 1 Photons 1 Proof of concept 1 Silicon compounds 1 Spatial resolution 1 Spectral range 1 Sum frequency generation 1 Super-resolution microscopy 1 Superresolution 1 Surface phonon-polaritons 1 Wide-field 1 Wide-field microscopies