PHOTOTHERMAL DISPLACEMENT MEASUREMENT OF TRANSIENT MELTING AND SURFACE DEFORMATION DURING PULSED-LASER HEATING

A photothermal displacement method has been developed to probe the pul sed laser-induced transient melting and surface deformation of Ni-P ha rd 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 t he pulsed laser heating. The deflection signals show the variation of the feature shape resulting from different pulse energies of the heati ng laser beam. The transient deflection signal also reveals that the t ime scale of the surface motion is in the range of several hundred nan oseconds. (C) 1998 American Institute of Physics. [S0003-6951(98)03141 -6].