Modeling VRALA,The Next-Generation Actuator For High-Density, Tick Secondary Mirrors For Astronomy

C. Del Vecchio[1], G. Agapito[1], G. Tomassi[2], and E. De Santis[2]
[1]National Institute for Astrophysics, Arcetri Astrophysical Observatory, Firenze, Italy
[2]University of Cassino, Cassino, Italy

The next-generation of Extremely Large Telescopes adaptive optics systems require high-order, long-stroke, quite large deformable mirrors. Higher forces and greater actuator densities than the ones provided by the current technology are needed, still maintaining the severe accuracy and bandwidth requests. Based on a very simple magnetic circuit, providing a compact device, the VRALA actuator accomplishes this very demanding goal. With an efficiency of about 7 N/W and an overall radius that allows actuator separations as low as 25 mm, the deformable mirror can be actuated with large forces on small spatial scales, with a little thermal impact, and/or its thickness can be increased, in order to simplify the manufacturing.