Photothermal Depth Profiling by Thermal Wave Backscattering and Genetic Algorithms

Photothermal depth profiling is usually applied to inhomogeneous materials to localize the optical inhomogeneity or retrieve the thermal effusivity depth profile by simply monitoring the photothermal signal after the pump beam excitation. In this paper the different kinds of inverse problems related to photothermal depth profiling are discussed, and the solutions given by thermal wave backscattering (TWBS) and genetic algorithms (GAs) are compared. Finally, the different performances and limits of validity on known linear profiles are compared.