A Micromachined Deformable Mirror for Adaptive Optics

摘要

The application of adaptive optics in astronomy requires increasingly compact deformable optical components with a high density of actuators, able to provide strokes of several micrometers. The main problem of the use of adaptive optics in more mainstream areas is the cost, the size and consequently the weight of the system. This paper presents the design and the results obtained with the deformable mirror under development. The system will have a continuous reflective membrane of 1 cm~2 driven by 64 closing gap actuators operating in contact. In the following this type of actuators is called "zipping actuators". Applying 100 V to some 800 μm wide zipping actuators results in an electrostatic force of 100 μN and a mirror displacement of 6 μm. Recent tests of the electric behaviour show linearity between applied tension and resulting displacement as well as a good reproducibility. We also present analysis and results obtained on silicon or polymer (BCB) membranes which have to be attached on the actuator array. A preliminary assembled component made of one actuator sealed to a 5 um thick polymer 5 x 5 mm~2 (BCB) membrane has demonstrated the feasibility of deforming such a small membrane by 3 μm, which is very promising.