Development of a line module type of SiC deformable mirror

Abstract

In this work, the complete development of a line module type silicon carbide (SiC) deformable mirror (DM) for adaptive optics (AO) is described. To eliminate the risk of fracture and misalignment during the simultaneous assembly of all actuators and the base plate of a DM, the line module concept is introduced. This line module is a pre-assembled set consisting of a line-shaped base plate to which actuators and flexures are glued in a row. This concept helps reduce the risk of actuator breakage during the assembly process while also providing flexibility by enabling the easy exchange of the line module if defective actuators are found. Flexible stand mounts are used to minimize mirror surface distortion caused by mounting. Distortions of the mirror faceplate in the complete assembly of the DM, caused by assembly tolerances, gravity, and temperature variations, are assessed through simulations. Considering the flattening of the mirror faceplate to its initial state, the distortions are found to be sufficiently low. Finally, the mirror surface stroke is checked with an interferometer, and the dynamic responses and coupling ratios are measured using a laser displacement sensor. The results show that the line module type SiC DM fulfils the design goals.

Keywords

• Adaptive optics
• deformable mirror
• optomechanics
• SiC mirror faceplate
• high-power laser