Evidence for phase-explosion and generation of large particles during high power nanosecond laser ablation of silicon

TitleEvidence for phase-explosion and generation of large particles during high power nanosecond laser ablation of silicon
Publication TypeJournal Article
Year of Publication2000
AuthorsYoo, Jong H., S. H. Jeong, Xianglei Mao, Ralph Greif, and Richard E. Russo
Secondary TitleApplied Physics Letters
Volume76
Pagination783-785
Publication Languageeng
Accession Number122
Keywordsablation, c, ca, circulation, crater, critical state, critical-state, deep, depth, dielectric, e, ejection, films, generation, irradiance, laser, laser ablation, laser-ablation, layer, lead, liquid, metal, model, nanosecond, nanosecond laser, particle, particles, particulates, phase explosion, phase-explosion, physics, power, sample, silicon, single-crystal, state, surface, thickness, threshold, time, time-resolved, transformation, transparency, usa, volume
Abstract

The craters resulting from high-irradiance (1x10(9)-1x10(11) W/cm(2)) single-pulse laser ablation of single-crystal silicon show a dramatic increase in volume at a threshold irradiance of 2.2x10(10) W/CM2. Time-resolved shadowgraph images show ejection of large particulates from the sample above this threshold irradiance, with a time delay similar to 300 ns. A numerical model was used to estimate the thickness of a superheated layer near the critical state. Considering the transformation of liquid metal into liquid dielectric near the critical state (i.e., induced transparency), the calculated thickness of the superheated layer at a delay time of 200-300 ns agreed with the measured crater depths. This agreement suggests that induced transparency promotes the formation of a deep superheated layer, and explosive boiling within this layer leads to particulate ejection from the sample. (C) 2000 American Institute of Physics. [S0003-6951(00)03206-X]

Notes

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LBNL Report NumberLBNL-44782
Citation Key14568