Subsurface-structure determination using photothermal laser-beam deflection

Abstract

Photothermal imaging using laser-beam deflection is shown to be a successful means of detecting subsurface structure in solids. Experimental data for known and unknown subsurface structures are reported. The existing theory agrees well with data on broad subsurface structures, but small subsurface structures produce signal variations which are better represented by a subsurface thermal contact resistance. The first photothermal-image characterization of a microscopic, unknown subsurface defect is presented.