A triple monochromator used as a spectrometer for Raman scattering

A triple monochromator was built for the study of light scattering in solids. The different monochromators were successively arranged in an additive and subtractive manner, so that for a 0.5 cm -1 resolution, a high rejection rate was obtained for stray light. Such a setting minimised geometrical aberrations, did not allow double diffraction and still gave a good signal to noise ratio. After studying the different parameters of the spectrometer, a comparison was made with a double monochromator showing its advantages in the low frequency shift region.