Modeling and evaluation of magnetic fluid deformable mirror with dual-layer actuators

Abstract

In this paper, a rectangular magnetic fluid deformable mirror (MFDM) with dual-layer actuators is proposed, which is designed to improve the correction performance for full-order aberrations. Compared with the conventional adaptive optics system that uses two mirrors to configure as a woofer–tweeter system, the proposed MFDM combines the two mirrors into one by using a two-layer layout design of the actuators. Firstly, based on the governing equations of the magnetic fluid, derived from the principles of conservation of fluid mass and magnetic field, the dynamics model of surface deflection of the MFDM is analyzed in Cartesian coordinates under the boundary conditions of the magnetic field and the kinematic conditions of magnetic fluid. Then, the analytical solutions of the surface movement of the mirror subject to the applied currents in the electromagnetic coils are obtained by properly separating the variables with truncated model numbers. Finally, the experimental results based on a fabricated prototype square MFDM show the effectiveness of modeling and the correction performance of the mirror for the full-order aberrations.