We report progress in the development of deformable mirrors (DM) using nanocomposite materials. For the extremely
large telescopes (ELTs) currently being planned, a new generation of DMs with unprecedented performance is a critical
path item. The DMs need to have large apertures (meters), continuous surfaces, and low microroughness. Most
importantly, they must have excellent static optical figures and yet be sufficiently thin (1-2 mm) and flexible to function
with small, low powered actuators. Carbon fiber reinforced plastics (CFRP) have the potential to fulfill these
requirements. However, CFRP mirrors made using direct optical replication have encountered a number of problems.
Firstly, it is difficult if not impossible for a CFRP mirror to maintain a good static optical figure if a small number of
plies are used, but adding more plies to the laminate tends to make the substrate too thick and stiff. Secondly, direct
optical replication requires precision mandrels, the costs of which become prohibitive at multi-meter apertures. We
report development of a new approach. By using a combination of a novel support structure, selected fibers, and
binding resins infused with nanoparticles, it is possible to make millimeter thick optical mirrors that can both maintain
good static optical figures and yet still have the required flexibility for actuation. Development and refinement of a
non-contact, deterministic process of fine figuring permits generation of accurate optical surfaces without the need for
precision optical mandrels. We present data from tests that have been carried out to demonstrate these new processes.
A number of flat DMs have been fabricated, as well as concave and convex DMs in spherical, parabolic, and other