Magnetic fluid deformation mirror for large scale aberration correction

With the increasing use of adaptive optics and large telescope projects, new requirements have been placed on wavefront correctors. The magnetic fluid deformable mirror is a new type of wavefront corrector that changes the ferrofluid surface by changing the strength of the external magnetic field. The advantage is that it can provide larger stroke deformation on the basis of satisfying the continuity of the reflecting surface. In this paper, in order to achieve 1mm aberration correction, the device and driving coils of the magnetic fluid deformable mirror are discussed. The coil with built-in permalloy material magnetic column is used as the driver of the magnetic fluid deformable mirror, and the parameters of the coil are designed and optimized. In order to meet the 1mm aberration correction requirement, the influence of the actuator on the magnetic fluid deformation was theoretically analyzed. The Comsol software was used for simulation, and the magnetic fluid deformation mirror was built for experimental verification. The results show that the designed driving coil can support the millimeter-level deformation of the magnetic fluid.