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Proceedings Paper

High-speed diagnostics in laser material processing applications
Author(s): Manfred Hugenschmidt; Ruediger Schmitt; Marion Althaus
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Paper Abstract

Present investigations at ISL are concerned with studies of fundamental processes related to the interaction of high- power pulsed laser radiation with matter. Target effects of this type are becoming increasingly important both in fundamental research and in numerous industrial laser processing applications. Optical methods including laser diagnostics have proven to provide valuable tools for achieving the necessary high resolution information required for optimizational purposes in these transient effects. Investigations will be reported by using both single pulse and repetitively pulsed IR-laser radiation, covering a large range of fluences and fluxes, typically above the plasma ignition threshold of any type of solid or liquid target material. Fast experimental diagnostics have been set up and used, allowing the basic physical parameters of laser induced absorption wave plasmas, such as electron densities and temperatures to be determined. High temporal and spatial resolution was achieved in spectroscopic measurements, including the evaluation of plasma emission line intensity ratios and Stark broadening. For high-speed photographic visualizational purposes an optical set-up was used, including a frequency doubled repetitively pulsed Nd-laser, properly synchronized to the high-power laser induced target effects under investigation. This sampling technique has even been shown to be useful in repetitively pulsed target experiments for obtaining a quasi-stationary imaging of the video technique. With minor modifications the resulting optical information has been obtained by interferometric, schlieren or shadowgraphic methods. Subsequent image recording was achieved by the use of CCD-cameras, allowing both storage and further numerical processing. Examples of laser impact studies, especially in the case of effects, as induced by repetitively pulsed CO2-laser radiation at average power densities above several to several tens of kW/cm2 with peak power densities in the multi-MW/cm3 range, will be given and discussed.

Paper Details

Date Published: 28 May 1997
PDF: 8 pages
Proc. SPIE 2869, 22nd International Congress on High-Speed Photography and Photonics, (28 May 1997); doi: 10.1117/12.273393
Show Author Affiliations
Manfred Hugenschmidt, French-German Research Institute Saint-Louis (ISL) (France)
Ruediger Schmitt, French-German Research Institute Saint-Louis (ISL) (France)
Marion Althaus, French-German Research Institute Saint-Louis (ISL) (France)


Published in SPIE Proceedings Vol. 2869:
22nd International Congress on High-Speed Photography and Photonics
Dennis L. Paisley; ALan M. Frank, Editor(s)

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