Distributed actuation systems for adaptive optics: from structural modeling to design optimization

Deformable mirrors are active optical systems used for wavefront control and correction of optical aberrations in many imaging and non-imaging applications such as microscopy, three-dimensional imaging, and medical or industrial applications. Their surface can be deformed by actuator arrays that are mounted below the reflective top-layer. While the performance increases as the density of actuators increases, scaling of the current mirror designs to the needed capabilities remains challenging. Well-engineered mirrors have actuator numbers ranging from 100 to 6000, but new concepts aim to achieve much denser arrays. A recently presented concept of a hysteretic deformable mirror features an actuator array of more than 16000 individually addressable locations, realized by 2D memory actuators utilizing piezoelectric hysteresis for stable shape configurations. A mechanical model has been proposed for describing the deformation of the reflective surface and predicting the accuracy of the mirror, while detailed multiphysics simulations were performed to investigate the behavior of the actuators in an array. Although this concept presents one possibility to achieve a high number of actuators with a design that relies on long-lasting technical components, we have also researched novel ways to realize new approaches for actuation systems. Kirigami actuators, whose mechanisms are grounded on geometrical cut patterns, can also open up the way for modular arrays used for deformable mirrors that will require a lightweight design.