Photothermoelastic probing for a clamped plate sample

In this paper we report a photothermal probing technique for a clamped thin plate sample that uses thermoelastic bending. Irradiation of the modulated laser light focused on the clamped plate sample generates the flexural vibration caused by thermoelastic bending. By scaning with the focused beam and optically sensing the bending, the irregularity of the plate is detectable nondestructively as changes in amplitude and phase of the flexural vibration. Characteristics of thermoelastic bending are also examined from the viewpoint of bending hot spot theory.