Fundamentals of laser‐solid interactions

The basic and dominant physical mechanism of laser interaction in absorbing media is heating. The temperature rise is determined by the laser power, pulse duration, absorption coefficient, specific heat and thermal diffusivity. It is possible to heat and melt thin surface layers of metals and semiconductors in a microsecond, or even nano‐ or picoseconds. The subsequent cooling rates may range from 10⁸ °C/sec to 10¹⁴ °C/sec. Annealing of ion‐implanted surfaces, laser glazing, surface alloying and cladding are technological applications based on the fast heating and cooling rates obtainable with short time irradiation of good absorbers with intense laser beams.