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Proceedings Paper

Investigation of a method for the determination of the focused spot size of industrial laser beams based on the drilling of holes in Mylar film
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Paper Abstract

The focussed spot size of industrial laser beams is a critical processing parameter in most laser machining applications as it determines the machined feature size and the irradiance produced by the laser at the material interface. There are a number of standard methods available for accurately measuring and analysing the focussed spot. These methods often require expensive equipment that can be time consuming and difficult to set up in a production environment. This paper presents an investigation into a cost effective and straightforward method for the measurement of focussed laser spot sizes based on drilling of holes in mylar film. It can be shown that the slope of a plot of the square of the hole diameter versus the natural log of the laser pulse energy is equal to twice the square of the spot radius. A measure of the laser spot size can be calculated by generating laser-drilled holes at number of laser pulse energies. The practicality and accuracy of this method is investigated in this paper for a number of laser types including a diode pumped solid state laser (UV DPSS) operating at the third harmonic (355nm), a femtosecond laser and a flash lamp pumped Nd:YAG laser. A comparison between the measured results and the results generated with other available techniques is also presented.

Paper Details

Date Published: 27 August 2003
PDF: 12 pages
Proc. SPIE 4876, Opto-Ireland 2002: Optics and Photonics Technologies and Applications, (27 August 2003); doi: 10.1117/12.463732
Show Author Affiliations
Helen Howard, National Ctr. for Laser Applications (Ireland)
Alan J. Conneely, National Ctr. for Laser Applications (Ireland)
Gerard M. O'Connor, National Ctr. for Laser Applications (Ireland)
Thomas J. Glynn, National Ctr. for Laser Applications (Ireland)

Published in SPIE Proceedings Vol. 4876:
Opto-Ireland 2002: Optics and Photonics Technologies and Applications
Vincent Toal; Norman Douglas McMillan; Gerard M. O'Connor; Eon O'Mongain; Austin F. Duke; John F. Donegan; James A. McLaughlin; Brian D. MacCraith; Werner J. Blau, Editor(s)

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