Covering thickness measurement by photothermal method

In the present work, the high speed photothermal method is offered. In this method a photothermal response in time after the irradiation of sample by one short impulse is registered. For method realization the heat distribution theory in sandwich-type systems is developed and software for the design of thermal response after laser impulse irradiation (with given parameters) on such systems is created. The simulated temporal changes of temperature on the surface of steel sample covered by one varnish layer after its irradiation by 0.1 μs laser impulse with energy density of 1 Dg/sm² is also discussed. Use of speed detectors for registration of thermal response from the surface of the explored sample and use of the developed software allows to define its thickness at the known optical and physical parameters of covering.