Images of femtosecond laser plasma plume expansion into background air

Yalçın, Şerife; Tsui, Ying Y.; Fedosejevs, R.

doi:10.1109/tps.2005.845359

Cited by 12 publications

(2 citation statements)

References 5 publications

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“…[21][22][23][24][25] This capability becomes essential for a hydrodynamic understanding of the plume propagation and reactive scattering. Plasma emission begins on the target surface soon after the laser photons reach the surface.…”

Section: Resultsmentioning

confidence: 99%

Influence of spot size on propagation dynamics of laser-produced tin plasma

Harilal¹

2007

Journal of Applied Physics

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The plume dynamics in the presence of an ambient gas is very intriguing physics. The expansion of a laser-produced plasma in the presence of an ambient gas leads to internal plume structures, plume splitting, sharpening, confinement, etc. We investigated propagation dynamics of an expanding tin plume for various spot sizes using a fast visible plume imaging and Faraday cup diagnostic tools. Our results indicate that the sharpening of the plume depends strongly on the spot size. With a smaller spot size, the lateral expansion is found to be higher and the plume expansion is spherical while with a larger spot size the plume expansion is more cylindrical. Analysis of time resolved imaging also showed internal structures inside the plume.

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Section: Resultsmentioning

confidence: 99%

Influence of spot size on propagation dynamics of laser-produced tin plasma

Harilal¹

2007

Journal of Applied Physics

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“…In vacuo, laser ablation can be described as a free expansion [ 20 , 21 , 22 , 23 ] while the laser plume which develops in the presence of an environmental gas is physically much more complex involving timescales from picosecond to nanosecond and microsecond. After electron heating during the pulse, the lattice heats typically over a few picoseconds due to e-phonon coupling, raising the surface temperature well above the evaporation point.…”

Section: Introductionmentioning

confidence: 99%

Backward Flux Re-Deposition Patterns during Multi-Spot Laser Ablation of Stainless Steel with Picosecond and Femtosecond Pulses in Air

et al. 2021

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We report on novel observations of directed re-deposition of ablation debris during the ultrafast laser micro-structuring of stainless steel in the air with multi-beams in close proximity on the surface. This interesting phenomenon is observed with both 10 ps and 600 fs NIR laser pulses at 5 kHz repetition rate. Ablation spot geometries could be altered with the use of beam splitting optics or a phase-only Spatial Light modulator. At low fluence (F ~ 1.0 J cm−2) and pulse exposure of a few hundred pulses, the debris appears as concentrated narrow “filaments” connecting the ablation spots, while at higher fluence, (F ~ 5.0 J cm−2) energetic jets of material emanated symmetrically along the axes of symmetry, depositing debris well beyond the typical re-deposition radius with a single spot. Patterns of backward re-deposition of debris to the surface are likely connected with the colliding shock waves and plasma plumes with the ambient air causing stagnation when the spots are in close proximity. The 2D surface debris patterns are indicative of the complex 3D interactions involved over wide timescales during ablation from picoseconds to microseconds.

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