Optimized actuators for ultrathin deformable primary mirrors
Abstract
A novel design and selection scheme for surface-parallel actuators for ultrathin, lightweight mirrors is presented. The actuation system consists of electrodes printed on a continuous layer of piezoelectric material bonded to an optical-quality substrate. The electrodes provide almost full coverage of the piezoelectric layer, in order to maximize the amount of active material that is available for actuation, and their shape is optimized to maximize the correctability and stroke of the mirror for a chosen number of independent actuators and for a dominant imperfection mode. The starting point for the design of the electrodes is the observation that the correction of a figure error that has at least two planes of mirror symmetry is optimally done with twin actuators that have the same optimized shape but are rotated through a suitable angle. Additional sets of optimized twin actuators are defined by considering the intersection between the twin actuators, and hence an arbitrarily fine actuation pattern can be generated. It is shown that this approach leads to actuator systems with better performance than simple, geometrically based actuators. Several actuator patterns to correct third-order astigmatism aberrations are presented, and an experimental demonstration of a 41-actuator mirror is also presented.
Additional Information
© 2015 Optical Society of America. Received 7 January 2015; revised 10 April 2015; accepted 16 April 2015; posted 17 April 2015 (Doc. ID 231885); published 20 May 2015. Defense Advanced Research Projects Agency (DARPA) (W31P4Q-14-1-0008); National Aeronautics and Space Administration (NASA). We thank Xin Ning (Caltech) for help with the optimization algorithm and John Steeves (Caltech) for advice on mirror fabrication. We thank Dr. Harish Manohara (JPL) for providing access to the Microdevices Lab (MDL) cleanroom facilities for sample fabrication. We thank Dr. Risaku Toda (JPL) and Mr. Victor White (JPL) for processing equipment training and usage advice at the MDL. ML acknowledges the support of a postdoctoral grant from the French Defence procurement agency (DGA) held through Aix-Marseille University, France. Financial support from the Keck Institute of Space Studies and the Dow Resnick Bridge program at Caltech is gratefully acknowledged. A part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with National Aeronautics and Space Administration (NASA).Attached Files
Published - ao-54-15-4937.pdf
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Additional details
- Eprint ID
- 57683
- Resolver ID
- CaltechAUTHORS:20150520-080116235
- Defense Advanced Research Projects Agency (DARPA)
- W31P4Q-14-1-0008
- NASA
- Ministère de la Défense, Direction générale de l'armement (DGA)
- Created
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2015-05-20Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Resnick Sustainability Institute, GALCIT