Simultaneous raman and SEM imaging of mineral sections

Abstract text (incl. figure legends and references)

Raman spectroscopy is an excellent tool for analysing the chemical bonding and structure in mineral sections with high specificity. Raman mapping/imaging is typically combined with optical microscopy to provide correlated information on samples. Sometimes, optical imaging provides less contrast for mineralogical samples compared to scanning electron microscopy (SEM) images. However, combined SEM Raman instruments are relatively uncommon and often require the sample to be moved within the SEM chamber to a different analysis position. This movement makes it challenging to ensure the SEM and Raman measurements are accurately co-localised.

In this work, we demonstrate a combined SEM Raman system that is capable of simultaneous SEM and Raman imaging from the same sample area. Figure 1 illustrates a SEM image and a Raman image taken from a mineral section. Here, there is clear and accurate overlay between SEM and Raman features. Additionally, Raman imaging detected the presence of biotite which is not visible in the SEM image.

Figure 1: a) SEM image of mineral section b) Corresponding Raman image illustrating the distribution of rutile (green), oligoclase (red), biotite (blue) and amphibole (purple)