Abstract
The energy of the laser radiation that is applied to the workpiece during laser material processing has to be transformed effectively into usable process energy. The normal light absorptivity at those wavelengths for which high-power lasers are available today is quite low in case of dielectrics and in case of metals its value lies in the 10–40% region.1 When exceeding a critical intensity in general an increase of the absorptivity can be observed [12, 14]. Figure 9.1 shows this behavior in case of processing Cu using a pulsed Nd:YAG laser. At small intensities the reflectivity corresponds to the normal reflectivity, after exceeding the critical value of the intensity the reflectivity decreases to a value of almost zero. The decrease of the reflectivity is accompanied by an increase of the energy coupling into the workpiece.
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Wester, R. (2011). Plasma Physics. In: Poprawe, R. (eds) Tailored Light 2. RWTHedition. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-01237-2_9
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DOI: https://doi.org/10.1007/978-3-642-01237-2_9
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