Test results of an adaptive deformable mirror for future

The Technische Universiteit Eindhoven and Delft University of Technology have developed together with TNO Science and Industry a prototype of an adaptive deformable mirror for future large telescope systems to correct for optical wavefront distortions caused by the earth’s atmosphere. The deformable mirror consists of a thin continuous membrane on which a grid of low voltage electro-magnetical push-pull actuators, - located in an actuator plate -, impose the out-of-plane displacements. In the design variable reluctance actuators are used. The prototype has a closed loop bandwidth of 200 Hz and consists of 427 actuators with +/- 10 micron stroke and nanometer resolution. The design of the mirror is such that the mechanics, electronics and the control are extendable and therefore allow for scaling of the system to even larger number of actuators. These characteristics and the mW’s heat dissipation per actuator make the mirror suitable for current large and future extremely large telescopes. At the Euspen Annual Conference 2007 progress on the mirror development was presented. The mirror is now fully assembled and tested at the adaptive optics breadboard at TNO Science and Industry. The breadboard consists of an atmosphere simulator, a wavefront sensor and the prototype mirror with real time distributed control system. Results are shown on the static and dynamic performance of the mirror. The (static) optical quality is tested with an interferometer setup and the dynamical performance is tested on the adaptive optics breadboard.