High power cw CO_2 laser beam properties in a system with a variable focal length mirror

摘要

The system of a mirror with a variable focal length, controlled by pressure variations generated in a cooling medium behind the mirror plate, was developed and investigated for the high power cw CO_2 industrial laser. The mirror was tested under condition of the laser operation as inter and outer cavity mirror. The results of the experimental analysis confirm that the use of the controllable curvature mirror in the laser resonator allows the dynamic changes in the resonator configuration and corresponding modification of the lasers output characteristics. Measurements performed for the variable focal length mirror, integrated into the beam delivery system prove the possibility for the controllable dynamic adjustment of the focus position as well as the focus size in the range, which is dependent on the mirror location relatively to the focusing optics.