Raman Spectroscopy
What information can Raman spectral images provide?
A Raman spectral image contains a full Raman spectrum at each and every pixel of the image - these hundreds, thousands or even millions of spectra are used to generate false colour images based on material composition and structure:
- Raman peak intensity yields images of material concentration and distribution
- Raman peak position yields images of molecular structure and phase, and material stress/strain
- Raman peak width yields images of crystallinity and phase
Raman spectral images provide chemical and structural information about a sample which cannot be observed using tradition light microscopy. In particular they can be used to elucidate:
- Distribution of components, and grain/particle size
- Changes of crystallinity and phase across a sample
- Size and shape of contaminant particles
- Interaction/mixing of components at phase boundaries
- Distribution of stress/strain across a sample
- Raman spectral image of sulfur after rapid laser ablation, showing the distribution of three distinct elemental sulfur phases (red, green, yellow) on a glass microscope slide (blue).
- Raman spectral image of a 0.6 x 2.4 mm2 area of a pharmaceutical tablet, showing the distribution of aspirin (red), paracetamol (green), caffeine (blue) and cellulose (yellow)
