Simulation of phase transitions induced in gallium arsenide by combined laser radiation

We performed a numerical simulation of phase transitions in gallium arsenide that are induced by the combined action of nanosecond laser pulses initiating melting and an additional neodymium-glass laser irradiation enabling the control of the interface velocity. In the case of counterpropagating laser beams, a strong temperature dependence of the absorption factor at 1.06 mum occurs. It causes a thermal wave, which separates from the melting front and, propagating towards the neodymium-glass laser beam, screens the melt. For copropagating laser beams, regimes with a nonmonotonic time dependence of the melt depth may exist. (C) 2001 MAIK "Nauka/Interperiodica".