Abstract: A non-contact thermal imaging system based on infrared radiation detection is described which uses an energy source to provide a beam of energy that strikes a sample to be analyzed. The energy beam produces a thermal wave in the sample, there being infrared radiation emitted from the thermal wave. All of the infrared radiation emitted from the heated area of the sample is collected and directed to an infrared detector, to have a two-dimensional image of the sample. This is used to detect surface and sub-surface structure, defects, etc. The use of a focussed energy beam, such as a laser or electron beam, offers advantages. In this technique, all points of the sample are treated equally and the results are very easily interpreted to know the exact location and type of structure that is imaged in the heated area.