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FIZIKA A 7 (1998) 4, 205 - 212
 
NITROGEN LASER BEAM INTERACTION WITH COPPER SURFACE
VIŠNJA HENČ-BARTOLIĆa, ŽELJKO ANDREIĆb, MIRKO
STUBIČARc
and H.-J. KUNZEd
aUniversity of Zagreb, Faculty of Electrical Engineering
and Computing,
Division of Applied Physics, Unska 3, 10000 Zagreb, Croatia
bRudjer Bo sković Institute, Dept. of Material Science, Thin
Films Laboratory,
Bijenička 54, 10000 Zagreb, Croatia
cUniversity of Zagreb, Faculty of Science, Dept. of Physics,
Bijenička 32,
10000 Zagreb, Croatia
dRuhr Universität Bochum, Institut für Experimentalphysik
V,
44780 Bochum, Germany
Received 29 October 1998; revised manuscript received 22 January 1999
Accepted 8 February 1999
The ultraviolet and visible spectra of plasmas produced by N2-laser
radiation focused onto a copper target in air and in vacuum have been recorded
photographically. The nitrogen laser beam (l = 337 nm) had a
maximum energy density of 1.1 J/cm2, the pulse duration was 6 ns, and the
repetition rate 0.2 Hz. The measured electron temperature was 15000 K (±30%)
in air and 13000 K (±50%) in vacuum and the electron densities
were 6.5×1017 cm-3 (±60%) and 3.0×1017
cm-3 (±60%), respectively. The irradiated surface
in air and in vacuum was studied employing a metallographic microscope. In vacuum, the
droplets were created and expulsed at the crater edges. Their formation is explained by
the hydrodynamical model. They were formed in a time interval which is about two times
shorter than the duration of the laser pulse. In air, droplets were also formed. The
weight loss from the Cu-crater in vacuum was about 0.3×10-4 mmole/pulse, in air it was about three times less.
PACS numbers: 52.50.Jm, 61.80.Ba
UDC 533.9
Keywords: laser-induced plasma, N2-laser radiation, short pulses, copper
surface
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