Abstract
In spite of the fact that more than five decades have passed since the invention of laser, some topics of laser-matter interaction still remain incompletely studied. One of such topics is plasma impact on the overall phenomenon of the interaction and its particular features, including influence of the laser-excited plasma re-radiation, back flux of energetic plasma species, and massive material redeposition, on the surface quality and processing efficiency. In this paper, we analyze different plasma aspects, which go beyond a simple consideration of the well-known effect of plasma shielding of laser radiation. The following effects are considered: ambient gas ionization above the target on material processing with formation of a “plasma pipe”; back heating of the target by both laser-driven ambient and ablation plasmas through conductive and radiative heat transfer; plasma chemical effects on surface processing including microstructure growth on liquid metals; complicated dynamics of the ablation plasma flow interacting with an ambient gas that can result in substantial redeposition of material around the ablation spot. Together with a review summarizing our main to-date achievements and outlining research directions, we present new results underlining importance of laser plasma dynamics and photoionization of the gas environment upon laser processing of materials.
Highlights
More than five decades have passed since the invention of laser during which laser-matter interaction has become an essential integral technique for modern technologies of material processing, direct writing of integrated optical devices, tailoring properties of existing materials, and synthesis of new nanostructured materials [1,2,3,4]
To gain insight into dynamics of air ionization by fs laser pulses under the conditions of works [17,18], we have developed a simple geometric approach [19], which takes into account laser beam reflection from the target and overlapping of the reflected and incoming beams
As shown in [32], the effect connected with the transverse oscillations of the ablation plumes upon its focusing in the presence of an ambient gas can be observed at fs laser ablation regimes that calls for further studies. Such oscillations are a natural feature of plume expansion dynamics, which can be superimposed with the plasma pipe effect and most probably are damped with increasing ambient pressure
Summary
More than five decades have passed since the invention of laser during which laser-matter interaction has become an essential integral technique for modern technologies of material processing, direct writing of integrated optical devices, tailoring properties of existing materials, and synthesis of new nanostructured materials [1,2,3,4]. Application of the hydrodynamic model reveals a complicated shock wave structure combining a quasi-cylindrical compressive wave propagating radially outward the laser beam axis and a half-spherical wave moving away from the irradiation spot on the target (Figure 3c). Such structures can be recognized in a number of experiments on visualization of laser ablation plume dynamics [28,29]. Such oscillations are a natural feature of plume expansion dynamics, which can be superimposed with the plasma pipe effect and most probably are damped with increasing ambient pressure
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
