  Hyperspectral microscopy is an imaging technique that provides spectroscopic
information with high spatial resolution. When applied in the relevant
wavelength region, such as in the infrared (IR), it can reveal a rich spectral
fingerprint across different regions of a sample. Challenges associated with
low efficiency and high cost of IR light sources and detector arrays have
limited its broad adoption. We introduce a new approach to IR hyperspectral
microscopy, where the IR spectral map of the sample is obtained with
off-the-shelf components built for visible light. The technique is based on the
nonlinear interference of correlated photons generated via parametric
down-conversion. We demonstrate chemical mapping of a patterned sample, in
which different areas have distinctive IR spectroscopic fingerprints. The
technique provides a wide field of view, fast readout, and negligible heat
delivered to the sample, which makes it highly relevant to material and
biological applications.
