The vibrational Raman spectrum provides a fingerprint which characterises chemical and molecular structure. The spectroscopic information can be regarded as similar in content, but often superior to that provided by Infra-Red (IR) spectroscopy, namely due to the much higher spatial resolution available through confocal Raman microprobes. Raman scattering is an inelastic light scattering process in which a laser photon is scattered by a sample molecule or crystal and loses energy during the process. The amount of energy loss is characteristic of the molecular bondings, thereby revealing the detailed nature of the investigated material. It enables highly specific chemical identification without ambiguity, in gas, liquid or solid phase, without requiring tedious and costly sample preparation.