Laser thermal-wave microscopy for remote nondestructive testing

摘要

Abstract: Consideration has been given to the laser thermal-wave microscopy method of nondestructive inspection that relies upon thermal wave excitation with flying laser spot and IR-radiometry registration of thermal waves. The theoretical analysis disclosed that contrast and amplitude of thermal image depend heavily on the relative position of the thermal beam and observation point, as well as on scanning velocity. The location of the thermal wave recording point at a distance of 1 or 2 thermal beam diameters ahead of the moving laser beam is optimum. The use of laser-scanning heat source and thermal wave recording with IR detector array improves greatly the inspection efficiency over the point-by-point technique of thermal wave recording. !5