Advances in Raman spectroscopy for the non-destructive subsurface analysis of artworks: Micro-SORS

A new analysis modality in Raman microscopy, Micro-Spatially Offset Raman Spectroscopy (micro-SORS) to explore the subsurface of materials in non-destructive and non-invasive way has been developed recently at ISPC - CNR. Micro-SORS facilitates the investigation of the chemical composition of subsurface, micrometre-scale-thick diffusely scattering layers at depths more than an order of magnitude larger than those accessible with the depth resolving power of conventional confocal Raman microscopy, avoiding need to resort to cross sectional analysis or sampling. First, an overall overview of research carried out at ISPC - CNR in the last five years concerning the development, optimization and application of micro-SORS to Cultural Heritage materials is provided. Additionally, we present new data achieved from the application of micro-SORS to illustrative micro-samples obtained from mediaeval polychrome sculptures of the Parma baptistery and Ferrara cathedral, highlighting further its potential in Cultural Heritage science.