Papers by Author: B. Gaković

Abstract: The effects of an Nd:YAG laser interaction with titanium target using laser radiation at wavelengths 1.064 or 0.532 μm (40 picoseconds pulse duration) were studied. Modification of target surfaces at laser energy densities of 2.4 and 10.3 J/cm2 (λ1 laser= 1.064 μm) and 1.1 J/cm2 (λ2 laser= 0.532 μm) are reported in this article. Qualitatively, the titanium surface modification can be summarized as follows: (i) ablation of the titanium surface in the central zone of the irradiated area for both laser wavelengths; (ii) appearance of a hydrodynamic feature like resolidified droplets of the material (λ1 laser= 1.064 μm), as well as formation of the wave-like microstructures (λ2 laser= 0.532 μm); and (iii) appearance of plasma, in front of the target, with both laser wavelengths.

Abstract: In this work we investigated the interaction of ns laser pulses (TEA CO2 and Nd:YAG) with a titanium nitride (TiN) thin film. The TiN thin film of 1μm thickness was deposited by PVD method on silicon substrate. Modification of TiN film was induced by laser pulses with power densities of about 108 and 109 W/cm2. Part of the laser energy absorbed on the target surface was converted into thermal energy and effects such as melting, vaporization and exfoliation were observed. Nd:YAG laser produced craters with sharp periphery, while TEA CO2 laser created damages with broad boundary zone. Hydrodynamic effects were especially pronounced during irradiation with TEA CO2 laser.

Abstract: The effects of TEA CO2 laser radiation on AISI 420 stainless steel and formed surface structures are studied. The laser energy density of 45.0 J/cm2 has modified the target surface. Qualitatively, the modifications of AISI 420 steel can be summarized as follows: change of color after action of one laser pulse; central zone of interaction in crater like form and periphery zone of interaction (for more than 10 laser pulses); appearance of grainy features and ablation rate of near 4 nm per laser pulse (action of 400 laser pulses); hydrodynamical effects like resolidified rim and droplets.