Laser-flash photographic studies of Er:YAG laser ablation of water

摘要

Photographic studies of pulse infrared laser irradiation of a pure-water target illustrate two aspects of mass removal: (1) surface evaporation, and (2) explosive vaporization. A pulsed Erbium:YAG (Er:YAG) laser provided radiation at a 2.9 $mu@m wavelength for delivery to the target site and triggered a second visible laser (nitrogen/dye laser) for illumination of the target site for photography. A variable time delay between the Er:YAG and dye lasers allowed selection of the time of the photograph ($GREQ 1 $mu@s). The photographs distinguish between (1) rapid surface evaporation when the energy deposition achieves high temperatures but does not supply the full enthalpy of vaporization, and (2) explosive vaporization of water when the entire enthalpy of vaporization has been provided by the laser pulse.