Low fluence laser sputtering of gold at 532 nm

Angle velocity distributions of 532 nm laser sputtered gold atoms are measured. No emission is seen at low fluence unless melt structure is first induced on the gold surface. Following melting, the velocity distribution at 1.4 J/cm2 is Boltzmann at 6500 K and the angular distribution is cosine. At 4.9 J/cm2 the angle velocity distribution shows collisional modification. These data contradict thermal sputtering but may result from surface plasmon excitation.