Ablated nano-particles residing in air: characterization, elimination, and role in pulsed microdrilling

Laser ablation of materials in air is able to introduce long living modification of the gas environment in vicinity of the exposed area. Such a modification implies formation and residence of small particles of the material and of ablation products. If the material is exposed to multipulse laser action, which is normally the case for micro-mashining, ignition of laser plasma at such particles is able to create significant screening of incident radiation, influencing this way formation rates and morphology of ablated structures. Effect of this low-threshold air breakdown is especially pronounced in long drilled channels, where convection is poor.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.