(1997)
Publication Type: Thesis
Publication year: 1997
Publisher: Meiesenbach
Edited Volumes: Fertigungstechnik - Erlangen 62
City/Town: Bamberg
The aim of the thesis was the development of a control circuit for high power CO2 laser beams. This combines innovative sensors and actuators to form a complete closed-loop-control. For online diagnostics of the laser beam parameters, measurement systems based on thermos-electrical detectors with extremely high dynamics (atomic layer thermopiles) were developed. Integration into a commercial laser system with flying optics and HF-excited laser source allows comprehensive analysis of disturbances. The resulting control system was divided into two subsystems for separate optimization. Laser beam power is controlled through a two-step controller using the rf-generator as actuator. This improves power stability more than the factor 100 without negatively affecting laser efficiency. The focus parameters are determined online through indirect measurements in the vicinity of the focussing optics. The highly dynamic adjustment occurs through two adaptive optics. This system fulfils the fundamental requirements for integration into commercial laser systems due to its compact design, ease of application and avoidance of moveable mechanical components.