By probing transient optical reflectivity, we have investigated the liquid phase epitaxial regrowth kinetics of ion‐implanted silicon during laser annealing. For annealing of ion‐implanted silicon with an 80‐ns (FWHM) pulse of various intensities at 1.06 &mgr;m, the threshold energy density required for melting is observed to be a constant. Above this threshold value, annealing occurs via an amorphous‐to‐liquid‐to‐crystalline transition. Redistribution of As profiles as measured by He+backscattering spectra is observed only when the incident energy density exceeds the threshold. Below this value, a reduction of dechanneled fraction is observed, but no dopant redistribution occurs. From the observed melting onset, a maximum heating rate of about 2×1010deg sec−1is observed.