Bulg. J. Phys. vol.43 no.2 (2016), pp. 110-120

The Effect of Process Parameters in Femtosecond Laser Micromachining

K. Garasz1, M. Tański1, M. Kocik1, E. Iordanova2, G. Yankov2, S. Karatodorov2, M. Grozeva2
1Centre for Plasma and Laser Engineering, The Szewalski Institute of Fluid Flow Machinery, Polish Academy of Sciences. Fiszera 14, 80-231 Gdańsk, Poland
2Laboratory of Metal Vapour Lasers, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria
Abstract. The paper presents extensive parametric study on ultrashort pulse laser micromachining of different materials. The experiment was conducted using SpectraPhysics femtosecond laser system. The laser offers 35 fs pulses with tunable wavelength and 1 kHz repetition rate. Therefore, the system itself allows to perform a complex research for a wide range of various parameters and materials.
Laser micromachining is a process based on a laser ablation phenomenon, i.e. microscopic removal of the material from the sample surface during laser irradiation. The process is strongly dependent from the applied laser radiation parameters and is considered the most precise method of material removal. The use of femtosecond laser pulses in micromachining allows a high concentration of energy within a single laser pulse and enables the detachment of particles from the irradiated target without any thermal damage to the surrounding material. The removal of the material occurs in the Rayleigh range from the laser focus.
The effect of laser fluence, wavelength, and machining process velocity on the crater size was measured and analyzed. It has been established, that the quality and efficiency of laser ablation process using femtosecond pulses allows to avoid most of the unwanted effects of the heat affected zone. The use of ultrashort laser pulses creates therefore an attractive opportunity for precise micromachining of many groups of materials.

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