Supercontinuum-based Fourier transform infrared spectromicroscopy

Fourier-Transform infrared (FTIR) spectromicroscopy combines the spatial resolution of optical microscopy with the spectral selectivity of vibrational spectroscopy. At the highest performance in far-field setups using broadband sources, FTIR spectromicroscopy can be done at synchrotron sources, providing diffraction limited spatial resolution thanks to the high brightness and temporal incoherence of the source. However, the increasing need for accurate and highly spatially resolved characterization of biological and inorganic materials is calling for alternative sources that would complement synchrotron radiation. Therefore, the development of alternative light sources is under heavy investigation. Up to now, low brightness of thermal emitters or high temporal coherence of laser sources have hindered the progress of bench top FTIR spectromicroscopy with micrometer to sub-micrometer level spatial resolution. Here, we demonstrate that fiber-based supercontinuum sources in the mid-infrared can enable fast spectral mapping of localized material properties with near to diffraction limited resolution and pave the way to table top, on demand, fast and highly spatially resolved characterization of organic materials.