In Raman spectroscopy, laser choice is important. The laser wavelength chosen will impact Raman intensity, spatial resolution, background fluorescence, acquisition time, and the potential cost of a Raman system.

Lasers used in Raman spectroscopy range from the UV into the near-infrared. Different wavelength regions offer advantages and disadvantages with the final laser selection. Some samples can be analysed at any wavelength with no issues, for example toluene, but for many samples laser wavelength choice is crucial for high quality Raman spectra .

UV (254nm laser, ) and visible lasers (532nm laser, 638nm laser ) require shorter accumulation times and can be used at lower laser power than near-infrared lasers(785nm laser).

Figure 1 shows the difference in Raman intensity between a 638 nm laser and a 785 nm laser using a silicon sample under the same conditions.