Development of key adaptive mirror technologies for the European Extremely Large Telescope (ELT)

Low stress bonding provides a significant technological advantage in attaching actuators and support structure to mirror surfaces to minimise the effects of print through. Hydroxide catalysis bonding produces a high strength covalent bond with demonstrated sustained shear stresses of greater than 2.5MPa. The extremely thin bond lines achievable (~100nm) should enable good acoustic coupling for the surface sensing aspect of the project. We will build on research work carried out within the department which has established that the bonding technology is viable with silicon carbide and apply this knowledge to the specific materials required for deformable mirrors whose use could be of high significance for future Extremely Large Telescopes (ELTs).