Investigation of plumes produced by material ablation with two time-delayed femtosecond laser pulses

Analytical performances of laser-induced micro-plasma of Al samples with single and double ultrashort pulses in air and with Ar-jet: A comparative study

“…With 50 fs pulses, the total plasma intensity with double pulses of 20 µJ (220 µJ) was 100 times higher than the one with a single pulse of the same pulse energy (120 µJ), and 50 times higher than the one with a single pulse but with a doubled pulse energy (140 µJ). Our observations on ultrashort double pulse ablation have been confirmed in similar studies in [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36].…”

“…The analysis of our results and those obtained in [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] has revealed the fundamental role of the electron-lattice relaxation time ( el .  1-10 ps) for laser ablation regime and the resulting double pulse LIBS-features.…”

The role of plasma shielding in collinear double-pulse femtosecond laser-induced breakdown spectroscopy

“…Hohlfeld et al 38 showed that decreases as the electron and lattice temperatures equilibrated. Noel et al 4 postulated that at short delays, before the electron and lattice could equilibrate, the high allows the energy of the second pulse to penetrate more deeply. This effect would favor increased nanoparticle production and ablation efficiency.…”

“…The smaller heat-affected zone is a consequence of the direct vaporization of the target, as opposed to ablation occurring through multiple steps, relying on melting and other thermal processes initiated by ns pulses. 4 Direct vaporization also makes the ablation process more stoichiometric as compared with ns-LIBS, where the pulse duration is long enough to interact with the plasma, ablation plume, and the thermally-affected zone. 5 Previous work has shown that the sensitivity of fs-LIBS may be further enhanced by splitting the laser pulse into two sub-pulses and delaying the arrival of the second pulse to maximize the signal/background ratio.…”

“…[6][7][8][9][10] Other studies, utilizing mass spectrometry, have found that double pulses (DPs) significantly increase the number density and kinetic energy of ions in the ablation plume. 4,[11][12][13][14][15] 4 addition, we use particle-in-cell (PIC) calculations to model the expansion of the plasma generated by the first pulse to determine under what conditions it can shield the surface from the second pulse.…”