Control systems for adaptive optical systems in high power laser resonators

The proposed research project aims at generalizing the existing concepts for continuous wave lasers towards a transversal beam shaping of mode-locked oscillators. For realizing a stable, pulsed laser beam, a coherent superposition of different longitudinal electromagnetic modes is necessary. In addition, nonlinear optical effects are needed – for instance by means of semiconductor saturable absorbers. This circumstance results in intensity-dependent set points. The proposed research project aims as compensating for these effects using intra-cavity deformable mirrors in order to enlarge the power-range of stable mode-locking. For achieving this goal, a model-based control design of the adaptive resonator is proposed. Thus, the complex and coupled dynamics of the mode-locked laser resonators has to be modeled in a transient way. Especially the dynamics of the optically addressed deformable mirror (OADM) give rise to advanced late lumping control approaches. Finally, the different actuator concepts – spherical pneumatic mirrors as well as an OADM – are combined in order to influence the (temporal) shape of the laser pulses. The chosen methods allow a deeper understanding of mode-locked lasers and aim a meeting the demand of compensation schemes in pulsed lasers.

DFG Programme Research Grants