RESUMO
The polarization state of the excitation light used in two Raman systems was controlled to study its effect in the unpolarized Raman spectra of unstructured samples. Both systems work in different regions of the electromagnetic spectrum (NIR and visible). Four polarization states (linear, linear at 45° and 90°, and circular) were used to excite liquid samples (ethanol, acetone, and their mixture). The results show that the Raman peaks intensities' ratio varies according to the polarization state of the excitation light. Peaks related to functional groups and C-H stretching modes increase their intensity when circular polarization (CP) is applied. The latter may help to study liquid mixtures with low concentrations. Different polarizing light states give a more detailed spectroscopic analysis since it gathers more structural information of the samples tested in this work with an undefined structure.
