Raman Spectroscopy detects light that has been inelastically scattered by an illuminated sample. The spectrum of that light provides a fingerprint by which molecules can be identified and small changes in molecular concentration, structure, or environment can be measured and mapped in 2D or 3D space. Any application where non-destructive, microscopic, chemical analysis and imaging is required. It can be used to image and characterize the chemical composition and structure of most non-metallic samples whether in solid, liquid, gas, powder, or some other form.
Infrared Spectroscopy measures the absorption of Infrared (IR) light as a function of wavelength by the molecules in a sample. The sample can be solid, liquid or gas. The infrared photons induce vibrational excitation of dipoles in polar molecules. The different vibrational modes of the molecules (e.g., bending, stretching, scissoring, rocking and twisting) have characteristic frequencies and combine to give a nearly unique spectral fingerprint for each compound. Because of that specificity, Infrared Spectroscopy is widely used to identify organic compounds and unknown polymers. (e.g., in forensic studies & in reverse engineering of materials).