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Initial Performance Results for High-Aspect Ratio Gold
MEMS Deformable Mirrors
Bautista Fernández and Joel Kubby
Department of Electrical Engineering
University of California, Santa Cruz
1156 High Street, MS:SOE2
Santa Cruz, CA 95064
ABSTRACT
The fabrication and initial performance results of high-aspect ratio 3-dimensional Micro-Electro-
Mechanical System (MEMS) Deformable Mirrors (DM) for Adaptive Optics (AO) will be discussed.
The DM systems were fabricated out of gold, and consist of actuators bonded to a continuous face
sheet, with different boundary conditions. DM mirror displacements vs. voltage have been measured
with a white light interferometer and the corresponding results compared to Finite Element Analysis
(FEA) simulations. Interferometer scans of a DM have shown that ~9.4um of stroke can be achieved
with low voltage, thus showing that this fabrication process holds promise in the manufacturing of
future MEMS DM’s for the next generation of extremely large telescopes.
Keywords: Adaptive Optics, High-Aspect Ratio MEMS, Large-Stroke Deformable MEMS Mirrors
Introduction
Future astronomical telescopes will require the use of large-stroke deformable mirrors. Current
MEMS DM technology has not yet met the requirements. Table 1 contains the MEMS DM
specifications for the TMT AO system. The devices described in this paper are a step closer to
achieving the ~10μm of stroke as required by the Thirty Meter Telescope (TMT). Unlike current
MEMS DM’s that are limited in their stroke by the thin (microns) sacrificial layers in the low-aspect
ratio surface micromachining fabrication process, the devices described in this paper have been
fabricated with a high-aspect ratio LIGA process that allows thick (tens to hundreds of microns)
material layers, and thus larger-stroke DM’s to be fabricated.
Table 1. MEMS DM specifications for TMT AO System
1
MEMS Adaptive Optics III, edited by Scot S. Olivier, Thomas G. Bifano, Joel A. Kubby, Proc. of SPIE
Vol. 7209, 72090O · © 2009 SPIE · CCC code: 0277-786X/09/$18 · doi: 10.1117/12.809617
Proc. of SPIE Vol. 7209 72090O-1
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