Role of ambient gas in heating of metal samples by femtosecond pulses of laser radiation
V.P. Zhukov1, N.M. Bulgakova2
1 Institute of Computational Technologies SB RAS, zukov@ict.nsc.ru
2 Kutateladze Institute of Thermophysics SB RAS
Keywords: femtosecond laser pulses, multiphoton ionization, metal target, ambient gas, residual heat
Pages: 165-176
Abstract
In this work we consider an experimentally observed effect of significant increasing of the residual heat in metal targets at their irradiation with femtosecond laser pulses in an ambient gas in respect to the vacuum conditions. Numerical modelling of heating of a platinum target by femtosecond laser pulses in argon under normal conditions has been performed taking into account gas breakdown in the focussing region of the laser beam in front of the target. The applied model is based on a combination of a thermal model describing heating and phase transitions in irradiated samples and a hydrodynamic model to describe motion of the ambient gas perturbed by laser irradiation as a result of multiphoton ionization. The hot ambient gas is shown to heat efficiently the irradiated sample. The hydrodynamic processes in the ambient gas play an important role in heating.
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