TY - JOUR

T1 - Pulsed Laser Ablation of Zinc in Tetrahydrofuran

T2 - Bypassing the Cavitation Bubble

AU - Wagener, Philipp

AU - Schwenke, Andreas

AU - Chichkov, Boris N.

AU - Barcikowski, Stephan

PY - 2010/4/2

Y1 - 2010/4/2

N2 - We applied a high-power (25 W) picosecond-pulsed laser system in combination with fast scanner optics for pulsed laser ablation in liquids in order to generate zinc/zinc oxide nanoparticles in tetrahydrofuran with optimized efficiency. Systematic variation of repetition rate and interpulse distance of subsequent laser pulses strongly affects the ablation efficiency. Shielding of subsequent laser pulses by induced cavitation bubbles could be minimized by these parameters. The analysis of experimental data results in a time constant of 55 μs concerning the cavitation bubble decay and a nonspherical shape with a lateral elongation of 120 μm after 100 μs. Regarding these parameters allows temporal and spatial bypassing of the cavitation bubble to enhance ablation efficiency and nanoparticle productivity. Furthermore, there is a nonlinear dependency of ablation efficiency on interpulse distance even if an effect coupled by cavitation bubbles can be excluded. We interpret this as a competition between two ablation mechanisms including thermal vaporization and phase explosion. For that purpose, we assume a transient preheating of the target by previous pulse, which leads to less efficient heat conduction that favors phase explosion instead of thermal vaporization. Calculations of 1D-heat conduction and analysis of generated nanoparticles support that interpretation. We were able to model the shape of the cavitation bubble and the experimental data by an adopted fit function.

AB - We applied a high-power (25 W) picosecond-pulsed laser system in combination with fast scanner optics for pulsed laser ablation in liquids in order to generate zinc/zinc oxide nanoparticles in tetrahydrofuran with optimized efficiency. Systematic variation of repetition rate and interpulse distance of subsequent laser pulses strongly affects the ablation efficiency. Shielding of subsequent laser pulses by induced cavitation bubbles could be minimized by these parameters. The analysis of experimental data results in a time constant of 55 μs concerning the cavitation bubble decay and a nonspherical shape with a lateral elongation of 120 μm after 100 μs. Regarding these parameters allows temporal and spatial bypassing of the cavitation bubble to enhance ablation efficiency and nanoparticle productivity. Furthermore, there is a nonlinear dependency of ablation efficiency on interpulse distance even if an effect coupled by cavitation bubbles can be excluded. We interpret this as a competition between two ablation mechanisms including thermal vaporization and phase explosion. For that purpose, we assume a transient preheating of the target by previous pulse, which leads to less efficient heat conduction that favors phase explosion instead of thermal vaporization. Calculations of 1D-heat conduction and analysis of generated nanoparticles support that interpretation. We were able to model the shape of the cavitation bubble and the experimental data by an adopted fit function.

UR - http://www.scopus.com/inward/record.url?scp=77951922254&partnerID=8YFLogxK

U2 - 10.1021/jp911243a

DO - 10.1021/jp911243a

M3 - Article

AN - SCOPUS:77951922254

VL - 114

SP - 7618

EP - 7625

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 17

ER -