Photothermal displacement measurement of transient melting and surface deformation during pulsed laser heating

Abstract

A photothermal displacement method has been developed to probe the pulsed laser-induced transient melting and surface deformation of Ni–P hard disk substrates. A probing He–Ne laser beam is aligned collinearly with the near-infrared nanosecond pulsed heating beam. The He–Ne beam spot is scanned on the microfeatures formed on the sample surface by the pulsed laser heating. The deflection signals show the variation of the feature shape resulting from different pulse energies of the heating laser beam. The transient deflection signal also reveals that the time scale of the surface motion is in the range of several hundred nanoseconds.