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Title: Laser ablation induced vapor plume expansion into a background gas. II. Experimental analysis

Abstract

Laser ablation of copper with a 4 ns laser pulse at 1064 nm was studied with a series of synchronized shadowgraph (100 fs laser pulses at 400 nm) and emission images (spectral line at 515 nm). Data were obtained at two laser pulse energies (10 and 30 mJ) and in three background gases (He, Ne, and Ar) at atmospheric pressure. The laser energy conversion ratio and the amount of sample vaporized for ablation in each condition were obtained by the theoretical analysis reported in paper I from trajectories of the external shock wave, internal shock wave, and contact surface between the Cu vapor and the background gas. All three quantities were measured from shadowgraph and emission images. The results showed that E, the amount of energy that is absorbed by the copper vapor, decreases as the atomic mass of the background gas increases; and M, the mass of the sample converted into vapor, is almost independent of the background gas [Horn et al., Appl. Surf. Sci. 182, 91 (2001)]. A physical interpretation is given based on the phenomena observed in shadowgraph and emission images during the first tens of nanoseconds after the beginning of the laser pulse for ablation inmore » different background gases. In addition, an internal shock wave was observed in the emission images during the first tens of nanoseconds after the laser pulse, which strikes the surface and should be one of the mechanisms inducing the liquid sample ejection. Also, a significant vortex ring near the target was observed in emission images at longer times after the laser pulse (>100 ns) which distorts the otherwise hemispherical expansion of the vapor plume.« less

Authors:
; ; ;  [1];  [2];  [2]
  1. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20982623
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 2; Other Information: DOI: 10.1063/1.2431085; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE; ABLATION; ARGON; ATMOSPHERIC PRESSURE; COPPER; ENERGY CONVERSION; EXPANSION; HELIUM; LASERS; LIGHT TRANSMISSION; NEON; PLASMA; PLASMA DIAGNOSTICS; PLUMES; PULSES; SHOCK WAVES; TRAJECTORIES; VAPORS; WALL EFFECTS

Citation Formats

Wen, Sy-Bor, Mao, Xianglei, Greif, Ralph, Russo, Richard E., Department of Mechanical Engineering, University of California, Berkeley, California 94720, and Lawrence Berkeley National Laboratory, Berkeley, California 94720. Laser ablation induced vapor plume expansion into a background gas. II. Experimental analysis. United States: N. p., 2007. Web. doi:10.1063/1.2431085.
Wen, Sy-Bor, Mao, Xianglei, Greif, Ralph, Russo, Richard E., Department of Mechanical Engineering, University of California, Berkeley, California 94720, & Lawrence Berkeley National Laboratory, Berkeley, California 94720. Laser ablation induced vapor plume expansion into a background gas. II. Experimental analysis. United States. doi:10.1063/1.2431085.
Wen, Sy-Bor, Mao, Xianglei, Greif, Ralph, Russo, Richard E., Department of Mechanical Engineering, University of California, Berkeley, California 94720, and Lawrence Berkeley National Laboratory, Berkeley, California 94720. Mon . "Laser ablation induced vapor plume expansion into a background gas. II. Experimental analysis". United States. doi:10.1063/1.2431085.
@article{osti_20982623,
title = {Laser ablation induced vapor plume expansion into a background gas. II. Experimental analysis},
author = {Wen, Sy-Bor and Mao, Xianglei and Greif, Ralph and Russo, Richard E. and Department of Mechanical Engineering, University of California, Berkeley, California 94720 and Lawrence Berkeley National Laboratory, Berkeley, California 94720},
abstractNote = {Laser ablation of copper with a 4 ns laser pulse at 1064 nm was studied with a series of synchronized shadowgraph (100 fs laser pulses at 400 nm) and emission images (spectral line at 515 nm). Data were obtained at two laser pulse energies (10 and 30 mJ) and in three background gases (He, Ne, and Ar) at atmospheric pressure. The laser energy conversion ratio and the amount of sample vaporized for ablation in each condition were obtained by the theoretical analysis reported in paper I from trajectories of the external shock wave, internal shock wave, and contact surface between the Cu vapor and the background gas. All three quantities were measured from shadowgraph and emission images. The results showed that E, the amount of energy that is absorbed by the copper vapor, decreases as the atomic mass of the background gas increases; and M, the mass of the sample converted into vapor, is almost independent of the background gas [Horn et al., Appl. Surf. Sci. 182, 91 (2001)]. A physical interpretation is given based on the phenomena observed in shadowgraph and emission images during the first tens of nanoseconds after the beginning of the laser pulse for ablation in different background gases. In addition, an internal shock wave was observed in the emission images during the first tens of nanoseconds after the laser pulse, which strikes the surface and should be one of the mechanisms inducing the liquid sample ejection. Also, a significant vortex ring near the target was observed in emission images at longer times after the laser pulse (>100 ns) which distorts the otherwise hemispherical expansion of the vapor plume.},
doi = {10.1063/1.2431085},
journal = {Journal of Applied Physics},
number = 2,
volume = 101,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}