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Proceedings Paper

Impact of ambient air medium on the surface profile of the material ablated with high-power lasers
Author(s): Shiv Raj Vatsya; Chengde Li; Suwas K. Nikumb
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Paper Abstract

MIcro machining of materials with high power ultra-short-pulsed lasers is becoming a preferred technique to obtain cleaner surface characteristics. Due to the short duration of the pulse, there is insufficient time to establish the thermal equilibrium. Consequently, ablation does not pass through the melting phase. Instead, it proceeds mainly with direct removal of the material at the molecular level. To fully benefit from these properties, a high quality beam profile is required. However, during processing the optical wave front suffers distortions while passing through the medium such as air. Passage through the medium causes the beam to self-focus and the gas breaks down, thus generating plasma, which distorts the geometrical and energy profiles of the beam. This phenomenon offsets the advantages of the procedure to a certain extent. For these reasons, processing is usually conducted in vacuum with associated inconvenience and expense. As a step towards improvement over the technique, we develop a numerical scheme to determine the beam profile in air medium. The profile of the beam is then used to determine the shape of the processed surface by a geometrical method developed recently. The calculated surface profile is compared with the experimental observations with good agreement. This provides a method to develop an understanding of the interactions of the laser beam, air and the material.

Paper Details

Date Published: 9 December 2004
PDF: 11 pages
Proc. SPIE 5578, Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education, (9 December 2004); doi: 10.1117/12.567473
Show Author Affiliations
Shiv Raj Vatsya, National Research Council (Canada)
Chengde Li, National Research Council (Canada)
Suwas K. Nikumb, National Research Council (Canada)


Published in SPIE Proceedings Vol. 5578:
Photonics North 2004: Photonic Applications in Astronomy, Biomedicine, Imaging, Materials Processing, and Education

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