Depth profiling of thermally inhomogeneous materials by neural network recognition of photothermal time domain data

Thermal conductivity depth profiles of thermally inhomogeneous materials are retrieved from the time dependence of the surface temperature after a flash illumination. A neural network method, which is trained to recognize the correlation between depth profiles and the surface temperature on the basis of many examples, is employed. Depth profiles retrieved from simulated noisy signals are shown and the average reconstruction errors are analyzed for different circumstances.