The determination of depolarization ratios can be made accurately with a laser Raman spectrometer, and the precision of the measurements is more a function of the sample than of instrumental performance. Therefore the discussion of depolarization measurements will commence with a brief analysis of the fundamentals of Raman emission from the sample. Thereafter the discussion will take into account the influence of the spectrograph on depolarization measurements. The conclusions to be drawn from the considerations, together with the application of well known optical laws, will permit optimum conditions to be defined for accurate depolarization measurements. Finally, a review of eight different experimental methods proposed and suggested conditions for their use will be given.
Charly D. Allemand, "Depolarization Ratio Measurements in Raman Spectrometry," Appl. Spectrosc. 24, 348-353 (1970)