Laser Raman Spectroscopy

Laser Raman Spectroscopy

Laser Raman spectroscopy depends on a change in the polarization of a molecule to produce Raman scattering. When a beam of photons strikes a molecule, the photons are scattered elastically (Rayleigh scattering) and inelastically (Raman scattering) generating Stoke’s and anti-Stokes lines.

Because Raman spectroscopy is a scattering process, samples of any size or shape can be examined. Very small amounts of material can be studied down to microscopic levels (~1µm).

Upside down volume rendering of a particle of TiO2 held on a glass slide by double-sided tape.
Streamline imaging

Instrument:

Renishaw InVia Reflex Raman Spectrometer

Three wavelengths available: 785nm, 633nm and 514nm and two gratings, 1800 and 1200 l/mm.

Also equipped with polarizer and half waveplate for each laser.

System Capabilities:

  • Microscope with Macro Point Accessory Kit, allowing analysis of powders, liquids, and films
  • StreamLine HR imaging, a high speed mapping function allowing the collection of thousands of datapoints in minutes. Minimum step size, 0.1 microns.
  • StreamLine imaging, allowing the collection of spatially resolved spectra with longer accumulation times.
  • Volume rendering (StreamLine HR acquisition)
  • Depth profiling

Selected Applications in industry:

  • Differentiation of carbon nanotube species (SWCNT, MWCNT)
  • Identification of corrosion products on various metal surfaces
  • Identification of different forms of carbon (e.g. diamond, graphitic, amorphous, diamond-like, nanotubes)
  • Detection of different inorganic oxides and, in some instances, their crystal form
  • Identification of micron-sized contaminants on photomasks
  • Identification of pigments in some paints and inks