High speed heterodyne infrared thermography applied to thermal diffusivity identification.

We have combined InfraRed thermography and thermal wave techniques to perform microscale, ultrafast (microsecond) temperature field measurements. The method is based on an IR camera coupled to a microscope and synchronized to the heat source by means of phase locked function generators. The principle is based on electronic stroboscopic sampling where the low IR camera acquisition frequency f(acq) (25 Hz) undersamples a high frequency thermal wave.