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Proceedings Paper

Characterization Of Real Laser Beam Profiles With Few Parameters For Metallurgical Applications
Author(s): Jacques Merlin; Jean Dietz; Carlos Oliveira
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Paper Abstract

In first approximation the material induced effects after laser beam interaction are function of the whole transmitted energy and of the local "irradiance" (in W.cm-2) levels and gradients. Consequently 3 informations may be able to describe this beam : carried power, shape and dimensions in the interaction zone. Thus shape and dimensions of a real beam would be simply and universaly described. If we are interested by the induced effects in the straight of the beam axis, 3 parameters are sufficient to describe the beam : the incident power P, an equivalent radius r+, and an axial "spread" factor of energy distribution g(E). These parameters have been mathematically defined but they are also experimentally measurable (in particular from transmitted power through a small aperture or a slit localised in the vicinity of the work zone). The experimental characterization of a 4 kW c.w. CO2 laser (CILAS CI 4000) has been carried out for several powers (between 200 W and 3 kW). When the power increases it has been find that r+ increases and g(E) stays nearly constant in spite of mode evolution. Presently the real-time evaluation of these parameters is investigating. Moreover these 3 parameters can be directly introduced in simplified analytical tridimensional thermal model, and so the behaviour expectation and the working parameters fluctuations effects (for example "mode" changes) become easier. At last this approach may be able to carry out "objective" comparison between the various high power lasers in different laboratories.

Paper Details

Date Published: 16 January 1988
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Proc. SPIE 0952, Laser Technologies in Industry, (16 January 1988); doi: 10.1117/12.968905
Show Author Affiliations
Jacques Merlin, INSA Lyon (France)
Jean Dietz, INSA Lyon (France)
Carlos Oliveira, CALFETMAT (France)


Published in SPIE Proceedings Vol. 0952:
Laser Technologies in Industry
Silverio P. Almeida; Luis Miguel Bernardo; Oliverio D.D. Soares, Editor(s)

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