Optimal Design of Adaptive Optics Based Systems Using High Fidelity MEMS Deformable Mirror Models

摘要

Over the last several years, MEMS deformable mirror technology has evolved from a specialized wavefront control device used by only a few select research organizations to a low cost and high performance product that can now be considered for inclusion in certain commercial machines and instrumentation. In a typical MEMS deformable mirror, a membrane is suspended over a pattern of electrostatic actuators, with the possibility of additional microstructures to affect the membrane movement. Because the electrostatic actuators in the MEMS deformable mirrors can only pull on the membrane surface and because the shape of the membrane itself is determined by the associated membrane mechanics, there are limitations and tradeoffs in the achievable shape corrections. Our research seeks to clarify and define: (1) the actual wavefront correcting capabilities of the different MEMS deformable mirror designs and (2) how to effectively design optical systems to best utilize this new technology. After describing a finite element model of a three layer MEMS deformable mirror technology, a method for integrating high fidelity models of deformable mirrors with commercial optical design and simulation software is described. We then suggest a design methodology for both evaluating the performance of the deformable mirror and optimizing the optical system itself to best utilize the MEMS deformable mirror such that the static optical elements are tailored to the specific shape correcting capabilities of the deformable mirror. Simulated results are presented of a defocus case study with more than 7 waves of correction, with the final results analyzed.