Control systems for adaptive optical systems in high power laser resonators

提出的研究项目旨在将现有的连续波激光器概念推广到锁模振荡器的横向光束整形。为了实现稳定的脉冲激光束，不同纵向电磁模式的相干叠加是必要的。此外，非线性光学效应是必需的，例如通过半导体可饱和吸收器。这种情况导致了依赖于强度的设定值。提出的研究项目旨在利用腔内可变形反射镜补偿这些影响，以扩大稳定锁模的功率范围。为了实现这一目标，提出了一种基于模型的自适应谐振器控制设计方法。因此，锁模激光谐振腔的复杂耦合动力学必须以瞬态方式建模。特别是光学寻址变形镜的动力学特性，提出了先进的后期集总控制方法。最后，将不同的致动器概念——球形气动反射镜和OADM——结合起来，以影响激光脉冲的（时间）形状。所选择的方法可以更深入地了解锁模激光器，并旨在满足脉冲激光器补偿方案的需求。

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.