/ Adaptive Optics Overview
In laser machines with changing beam path lengths (i.e. flying optic arrangements) the laser beam diameter and the phase front radius are continuously changing along the beam path. Consequently, the beam spot diameter at focus will become smaller with larger raw beam diameters and vice versa. Phase front variations lead to corresponding changes in the systems effective focal length ultimately changing the optimal working distance.
The adaptive optic can compensate for both the above mentioned and uncontrolled sources of processing problems, thus it represents an optimal technical solution. For complete control of the mentioned factors two Adaptive Optics are necessary.
The first adaptive mirror is usually inserted next to the laser output in the beam path and is controlled in such a way that the raw beam diameter onto the focusing optics remains constant and is an attractive alternative to the widely used motorized lens because of its capability to handle higher power levels. Without the addition of a second Adaptive Optic the focal length still changes with the phase front radius variations.
A second adaptive mirror, preferably installed before the focusing optics can be controlled in such a way that all systematic or accidental phase front radius variations are entirely compensated for, resulting in a consistent and constant focal length throughout the entire work space.