FOCAL PLANE DETERMINATION OF PULSED LASERS BEAMS BY USING LASER ABLATION INDUCED PHOTOACOUSTICS

D. J. O. ORZI; F. C. ALVIRA; G. A. TORCHIA; G. M. BILMES

Playa del Carmen

Conferencia; XI International Conference On Laser Ablation; 2011

High-power lasers are of increasing importance in industrial production for processing of materials, among others, as cutting, welding, drilling, micromachining and hardening. These applications require a very well control of the characteristics of the laser beam as power, polarization, position and size of the focused beams. In this paper we propose a faster and simpler method to determine the focal plane of a focused laser beam. We applied the procedure to a beam of a pulsed Ti:Sapphire (120 fs, 1 mJ, 1 kHz and 800 nm) infrared laser, used in a micromachining station, that processes materials. The method based on Laser Ablation Induced Photoacoustic (LAIP), register the acoustic signal generated during the ablation of the surface, as a function of the focusing distance. Figure 1 shows the determination of the focal plane during the processing of a dielectric used in microelectronics. The plot represents the acoustic signal generated during ablation as a function of DZ, the distance between the lens plane and the surface of the sample.