FIZIKA A 15 (2006) 3 , 181-192
CO2 AND Nd:YAG LASER RADIATION INDUCED DAMAGE IN ALUMINIUM
SHAZIA BASHIRa, M. S. RAFIQUEb, M. KHALEEQ-UR-RAHMANb,
FAIZAN-UL-HAQa and B. R. ALVINAa
aCentre for Advanced Studies in Physics, Government College University Lahore, Pakistan
bAdvanced Physics Laboratory, University of Engineering and Technology Lahore, Pakistan
Received 2 May 2005; Revised manuscript received 19 April 2006
Accepted 15 November 2006 Online 23 February 2007
The change in the electrical properties of pure aluminium (Al 99.999%) after
exposure to CO2 (energy =2.5 J/pulse, wavelength =10.6
mm, pulse duration = 200 nsec) and Nd:YAG (energy =10 mJ/pulse, wavelength =1.06
mm and pulse duration =12 nsec) laser radiation is investigated. The samples
were exposed to laser radiations for different numbers of pulses. The change in
electrical characteristics of Al is studied under different ambient conditions,
after irradiating the samples in air, vacuum and hydrogen at different pressures.
After exposure, the electrical conductivity of Al is measured by the four probe
method. The electrical conductivity decreases with increasing number of pulses.
The damage in air and in hydrogen is more pronounced than in vacuum which can be
attributed to collisionnal sputtering of Al by plasma ions of air molecules and
hydrogen, respectively. The change in the conductivity in hydrogen is pressure-dependent.
Some theoretical considerations are also made, e.g. the phonon speed in Al
during the photon interaction, minimal melting and evaporation energy per volume,
damage threshold energy, penetration depth, the mass of heated volume and
average temperature rise at the Al surface during laser irradiation.
PACS numbers: 61.80.Ba, 61.82.Bg
UDC 535.212, 537.312
Keywords: TEA CO2 laser radiation, Nd:YAG laser radiation, damage,
electrical conductivity, collisionnal sputtering