High efficiency Raman system for safe molecular characterisation of pigments

An innovative portable Raman system (exc. wav. 1064 nm) for safe molecular characterisation of pigments and other photosensitive materials has been developed and successfully tested. It was equipped with a novel probe, which has been designed and built in order to perform Raman scattering measurements on a relatively large area homogeneously irradiated at laser intensities lower than the typical ones needed using commercial instruments. Besides a set of original optical solutions providing improved efficiency, the instrument has also been equipped with an active thermal control line, which allows to prevent alterations of the material under study and to optimize the measurement cycles by means of suitable modulations of the laser power. Comparative tests of the novel analytical tool with an alternative setup equipped with a commercial Raman probe were carried out on a set of pure pigments and oil paint layers, which allowed assessing the higher measurement efficiency and reliability of the former with respect to the latter.