Testing of diffractive optical element as part of specific CO₂ laser equipment for metallic materials modification

Testing of a reflective diffractive optical element (DOE) as part of specific CO₂ laser equipment Oerlikon OPL 2000 for metallic materials modification was performed. The power density distribution in a plane located behind the DOE focal plane has been measured. It was found that DOEs make it possible to form a predetermined beam power density profile and to perform the transformation of laser energy, chosen by calculation previously. The use of these optical elements in the laser material treatment reveals new possibilities for controlling properties and operational characteristics of processed components. Additional redistribution of the beam power to edges of the laser spot is achieved by increasing the proportion of energy reflected by DOE peripheral zones, for example, by increasing the aperture of the focusable beam. It is proposed using a telescopic system of two lenses to change the aperture of the laser beam focusable by the DOE. (paper)