This spectroscopic technique complements another recently developed method of chemical characterisation or fingerprinting, namely micro-thermal analysis (micro-TA). This also uses an “active” SThM probe, which acts as a heater as well as a thermometer, so as to inject evanescent temperature waves into a sample and to allow sub-surface imaging of polymers and other materials. The sub-surface detail detected corresponds to variations in heat capacity or thermal conductivity. Ramping the temperature of the probe, and thus the temperature of the small sample region in contact with it, allows localized thermal analysis and/or thermomechanometry to be performed.