Product Code: ICAL08_P130

Effect of Laser Fluence on the Ablation Rate of Metals in the Infrared, Visible, and Ultraviolet Nanosecond Pulses Irradiation Regime
Authors:
Mihai Stafe, Univesity 'Politehnica' of Bucharest; Bucharest Romania
Ionut Vladoiu, Univesity 'Politehnica' of Bucharest; Bucharest Romania
Constantin Negutu, Univesity 'Politehnica' of Bucharest; Bucharest Romania
Ion M. Popescu, Univesity 'Politehnica' of Bucharest; Bucharest Romania
Presented at ICALEO 2008

We investigated the dependence of the ablation rate of metals on the fluence of nanosecond laser pulses with wavelengths of 1064, 532 and respectively 355 nm in atmospheric air. We assessed the ablation rate for fluence in the range of 0.1-200 J/cm2 by changing the irradiated area at the target surface. The experiments indicate three different domains of the ablation rate. The first domain is near the ablation threshold fluence (0.1-5 J/cm2, depending on the optical absorptivity of the target), and is characterized by an increase of the ablation rate according to the Arhenius law [1,2]. In the second domain, further increase of the fluence leads to a logarithmic increase of the ablation rate [1-5], the maximum ablation rate depending on thermal conductivity and oxidation behavior of the target. Increasing the fluence above a breakdown threshold value (50-150 J/cm2, depending on the wavelength and thermal properties of the target) gives the third domain in which the ablation rate has a jump and increases further steeply [4,5]. The jump of the ablation rate is due to the transition from a normal vaporization to a phase explosion regime, and to the change of the dimensionality of the hydrodynamics of the plasma-plume.