Depth profiling of thermophysical parameters of curved solids using photothermal technique

The effect of curved surface of both cylindrical and spherical samples with continuous gradient structure (e.g., case hardened surface) on the photothermal radiometric signal(PTR) are investigated. Using an appropriate signal processing, it is found theoretically that the curvature effect of both cylindrical and spherical samples can be, or partially can be suppressed under certain conditions and the PTR signal from the curved composite sample can be equivalent to that of a flat surface with the same structure.