Conference Publication Details
Mandatory Fields
Howard, H,Conneely, A,O'Connor, G,Glynn, T,Blau, WJ,Donegan, JF,Duke, AF,MacCraith, JA,McMillan, ND,OConnor, GM,OMongain, E,Toal, V,McLaughlin, JA
Investigation of a method for the determination of the focussed spot size of industrial laser beams based on the drilling of holes in Mylar film
OPTO-IRELAND 2002: OPTICS AND PHOTONICS TECHNOLOGIES AND APPLICATIONS, PTS 1 AND 2
2003
March
Published
1
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Optional Fields
laser processing beam measurement spot size measurement beam diagnostics
541
552
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.
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