Product Code: ICA12_905

Investigation of Thermal Lensing Time Constants in Laser Processing Optics
Authors:
Christiane Thiel, Institut fuer Strahlwerkzeuge, Univ. of Stuttgart; Stuttgart Germany
Rudolf Weber, Institut fuer Strahlwerkzeuge, Univ. of Stuttgart; Stuttgart Germany
Axel Hess, Institut fuer Strahlwerkzeuge, Univ. of Stuttgart; Stuttgart Germany
Thomas Graf, Institut fuer Strahlwerkzeuge, Univ. of Stuttgart; Stuttgart Germany
Presented at ICALEO 2012

High power solid state lasers at high beam quality undergo a rapid development these days. They are in demand for the manufacturing of, e.g., lightweight components and parts in the electronics industry. As shown in many publications, this brings up the problem of beam handling, i.e., allowing the beam to propagate to the material interaction zone with constant beam parameters. One of the challenges that engineers encounter is the focus shift induced especially by light-transmissive optical components. As this effect is strongly influencing material processing it is a major issue to measure and classify the temporal formation of the effect until steady-state condition is reached. The temporal behavior of the thermal lensing in standard laser welding optics was measured using different setups. A comparison between a fast and approximate method on the one hand and a more elaborate but also time consuming method on the other hand will be drawn. Parameters describing the temporal behavior of optics will be discussed.