Kibblewhite, Edward (Univ. of Chicago, Adaptive Photonics LLC)
The current generation of Monolithic Deformable Secondary Mirrors use a dense actuator spacing, both to achieve adequate fitting error and damping to the thin faceplate. Ground Layer AO can be effective with less actuators but damping may become more of a problem. A highly segmented architecture for the deformable secondary should be able to achieve good GLAO performance with less cost and complexity, especially for the next generation telescopes. This paper discusses the design of one such mirror optimized for a 12-meter class telescope. It is shown that the forces required to control the segments should be ≈ 0.02N/actuator and that the electronics can be integrated into the segment itself. Total power requirements of less than 100 watts/m2, with a total weight of less than 100 kg/m2 appear possible. The technology is directly scalable to the large DSMs required by ELTs.The use of single LGS beacons for wide field AO is also discussed. It is suggested that a single Rayleigh beacon can reduce the FWHM by a factor of over 2 over a 5 arc-minute field of view for a 12 m telescope at a site similar to Mauna Kea. A factor of 5 reduction may be possible over a 1 arc-minute field of view using a sodium beacon.
10.26698/AO4ELT5.0037- Proceeding PDF