Abstract

The propagation of long thermal waves through metal objects was investigated. These waves are created when the surface of an absorbing medium is subjected to a slowly modulated heat source. In this manner surface deformations large enough to be observed by holographic interferometry were induced in thin, flat aluminum plates. The oscillatory, wavelike deformations of interest are superimposed on a monotonically increasing deformation. Stroboscopic and otherwise modified forms of holographic interferometry are used to display only the wavelike portion. Predicted variations of fringe properties such as visibility and density are verified experimentally. The interaction of the long thermal waves with slots and holes in the plates is observed. The possible application of long thermal waves to holographic interferometry is noted.

© 1985 Optical Society of America