Laser ablation in air: nature of current pulses

Laser ablation in air was studied near the ablation threshold. Current pulses induced by the laser pulse in the target circuit as well as light pulses emitted from the near-target region were recorded as a function of laser fluence. The location of charge carriers responsible for the rise of current pulses was estimated. It was concluded that the plasma plume formed near the target is a source of radiation that ionizes air. The absorption coefficient of this photoionizing radiation was estimated.