Lasers for Raman Spectroscopy

The ”inelastic scattering of light”, or Raman effect, was observed in practice for the first time already in 1928 by C.V. Raman for which he was awarded the Nobel Prize in 1930. It is only in the last two decades, however, that Raman spectroscopy has begun to realize its potential as an almost universally applicable analytical technique, not only in material and life science research applications, but also as a process control tool in, for instance, pharmaceutical, food & beverage, chemical and agricultural industries.

A number of technology advancements in recent years have aided instrument manufacturers in overcoming the challenge of weak signals associated with Raman spectroscopy and enabled development of small, sensitive and user-friendly Raman instruments. These advancements include improvements in laser technology; smaller, more powerful lasers with more robust spectral performance at many different wavelengths, detectors; CCDs and InGaAs arrays that allow designs of instruments without moving parts, spectral filters; Volume Bragg Grating elements for more narrow notch filters, along with developments of new schemes for Raman signal generation and detection.

lasers for raman spectroscopy
An example of the resonance Raman effect; by choosing 355 nm rather than 473 nm laser excitation the observed Raman signals are much stronger, thus providing improved resolution. (Co W.R. Browne, Institute for Chemistry, University of Groningen, The Netherlands.